Genetic Engineering

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Genetic engineering is a combination of receptions, methods and technologies for obtaining recombinant RNA and DNA, genes of genes from the body (cells), carrying out manipulations with genes and introducing them to other organisms.

Genetic engineering is not a science in a broad sense, but is a biotechnology tool, using the studies of such biological sciences, such as molecular and cellular biology, cytology, genetics, microbiology, virology.

1 Economic value

2 Development history and technology achieved

3 Application in scientific research

4 man genetic engineering

5 Notes

7 literature

Economic importance

Genetic engineering is used to obtain the desired qualities of a variable or genetically modified organism. Unlike traditional selection, during which the genotype is subject to change only indirectly, genetic engineering allows you to directly interfere in the genetic apparatus using molecular cloning technique. Examples of the use of genetic engineering are obtaining new genetically modified grain crops, production of human insulin by using gennomified bacteria, the production of erythropoietin in cell culture or new breeds of experimental mice for scientific research.

The basis of the microbiological, biosynthetic industry is a bacterial cell. The cells necessary for industrial production are selected on certain features, the most important of which is the ability to produce, synthesize, with the highest possible amounts, a certain compound - amino acid or antibiotic, steroid hormone or organic acid. Sometimes it is necessary to have a microorganism capable of, for example, to use oil or wastewater as "food" or process them into biomass or even quite suitable for feed additives protein. Sometimes we need organisms that can develop at elevated temperatures or in the presence of substances, unconditionally fatal for other types of microorganisms.

The task of obtaining such industrial strains is very important, numerous techniques of active influence on the cell have been developed for their modifications and selection - from the processing of highly active poisons before radioactive exposure. The purpose of these techniques is one - to achieve changes in the hereditary, genetic device of the cell. Their result is to obtain numerous microbes-mutants, from hundreds and thousands of which scientists are then trying to select the most suitable for one purpose or another. The creation of techniques of chemical or radiation mutagenesis was an outstanding achievement of biology and is widely used in modern biotechnology.

But their ability is limited to the nature of the microorganisms themselves. They are not able to synthesize a number of valuable substances that accumulate in plants, primarily in medicinal and essential sufficient. Substances cannot be synthesized, very important for animal and human life, a number of enzymes, peptide hormones, immune proteins, interferons and many more simply arranged compounds that are synthesized in animal and human organisms. Of course, the possibilities of microorganisms are far from being exhausted. Of all the abundance of microorganisms used by science, and especially industry, only an insignificant share. For the purpose of selection of microorganisms, the bacteria of anaeroba, capable of living in the absence of oxygen, phototrofses using light energy like plants, chemoavtotrophy, thermophilic bacteria, capable of living at a temperature, as it turned out recently, about 110 ° C, and others.

Nevertheless, the limitations of "natural material" is obvious. Obtain restrictions tried and trying with the help of cultures of cells and plant tissues and animals. This is a very important and promising path, which is also implemented in biotechnology. Over the past few decades, scientists have created methods due to which individual cells of the plant or animal can be forced to grow and multiply separately from the body as bacteria cells. It was an important achievement - the resulting cell cultures are used for experiments and for industrial production of some substances that cannot be obtained using bacterial crops.

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Development history and technology achieved

In the second half of the twentieth century, several important discoveries and inventions underlying genetic engineering were made. Perennial attempts to "read" the biological information that is "recorded" in genes has successfully completed successfully. This work was launched by the English scientist F. Senger and American scientist U. Gilbert (Nobel Prize in Chemistry 1980). As you know, the genes contain information-instructions for synthesis in the body of RNA molecules and proteins, including enzymes. To force the cell to synthesize new, unusual substances for it, it is necessary that the corresponding sets of enzymes are synthesized. And for this you need or purposefully change the genes in it, or to introduce new, previously missing genes. Changes in alive cell genes are mutations. They occur under action, for example, mutagenes - chemical poisons or radiation. But such changes can not be monitored or directed. Therefore, scientists concentrated efforts to attempt to develop methods for introducing new, completely defined genes that needed people into a cell.

The main stages of the solution of the genetically engineering task are as follows:

1. Getting an isolated gene.

2. Introduction of a gene into a vector for transfer to the body.

3. Transfer of a vector with a gene into a modifiable organism.

4. Transformation of organism cells.

5. Selection of genetically modified organisms (GMOs) and elimination of those that were not successfully modified.

The process of gene synthesis is currently designed very well and even largely automated. There are special devices equipped with a computer in the memory of which the synthesis programs of various nucleotide sequences are laid. Such an apparatus synthesizes DNA segments up to 100-120 nitrogen bases (oligonucleotides). He received the spread of an technique, which allows to use for the synthesis of DNA, including a mutant, polymerase chain reaction. The thermal stable enzyme, DNA polymerase, is used in it for the matrix synthesis of DNA, as the seed of which is used artificially synthesized pieces of nucleic acid - oligonucleotides. The reverse transcriptase enzyme allows using such seeds (primers) to synthesize DNA on the matrix of RNA leaded from RNA cells. Synthesized in this way of DNA is called complementary (RNA) or cDNA. Isolated, "chemically clean" gene can also be obtained from the phage library. This is the name of the bacteriophage preparation, in which random fragments from the genome or cDNA reproduced by FAGOM together with all its DNA are built.

To integrate the gene in the vector, use enzymes - restictations and ligases, which are also a useful tool of gene engineering. Using restrictasis gene and vector can be cut into pieces. With the help of ligases, such pieces can be "glued", to connect in a different combination, constructing a new gene or entering it into the vector. For the opening of Restrictas Verner Arber, Daniel Natans and Hamilton Smith were also awarded the Nobel Prize (1978).

The technique of introducing genes in the bacteria was designed after Frederick Griffith discovered the phenomenon of bacterial transformation. The basis of this phenomenon is a primitive sexual process, which in bacteria is accompanied by the exchange of small fragments of non-chromosomal DNA, plasmids. Plasmid technologies formed the basis of the introduction of artificial genes into bacterial cells.

Significant difficulties were associated with the introduction of a finished gene in the hereditary apparatus of plants and animal cells. However, in nature, there are cases when foreign DNA (virus or bacteriophage) is included in the cell's genetic apparatus and using its exchange mechanisms begins to synthesize "its" protein. Scientists investigated the features of the introduction of alien DNA and used as the principle of introducing genetic material into the cell. This process was called transfection.

If one-cell organisms or cultures of multicellular cells are subjected to modifications, then at this stage the cloning begins, i.e. The selection of those organisms and their descendants (clones) that have undergone modifications. When the problem is set to obtain multicellular organisms, the cells with the changed genotype are used for vegetative reproduction of plants or introduced into the blastocysts of the surrogate mother when it comes to animals. As a result, young with a modified or unchanged genotype are born, among which only those that expect expected changes are selected.

Application in scientific research

Genetic knockout. To study the function of one or another gene, genetic knockout can be applied. This is the name of the removal technique of one or more genes, which allows to investigate the consequences of such a mutation. For knockout, the same gene or its fragment is synthesized, modified so that the gene product has lost its function. To obtain knockout mice, the resulting genetically engineered construction is introduced into embryonic stem cells and replace it with a normal gene, and the modified cells are implanted into the blastocysts of the surrogate mother. In fruit flock, drosophila mutation is initiated in a large population, in which they are then looking for offspring with the desired mutation. A similar way is obtained by knocut in plants and microorganisms.

Artificial expression. The logical addition of knockout is artificial expressions, i.e. Adding a gene to the body, which he had not previously had. This method of genetic engineering can also be used to study the functions of genes. In essence, the process of introducing additional genes is as follows, as with a knockout, but the existing genes are not replaced and are not damaged.

The label of gene products. Used when the task is to study the localization of the gene product. One of the methods of labeling is the substitution of a normal gene into a fusion with a reporter element, for example, with a genome of a green fluorescent protein (GRF). This protein fluorescent in the blue light is used to visualize the product of the gene modification. Although such an equipment is convenient and useful, its by-consequences may be partial or complete loss of the function of the studied protein. More sophisticated, although not so convenient method is the addition to the protein studied not as large oligopeptides, which can be detected using specific antibodies.

Study of the expression mechanism. In such experiments, the task is to study the conditions of gene expression. The features of expression depend primarily from a small section of DNA, located in front of the coding area, which is called the promoter and serves to show the transcription factors. This area is introduced into the body, putting a report carter after it instead of its own gene, for example, the same GFP or enzyme catalyzing well detectable reaction. In addition, the functioning of the promoter in certain tissues in one point or another becomes well noticeable, such experiments allow you to investigate the structure of the promoter, removing or adding DNA fragments to it, as well as artificially enhance its functions.

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Genetic engineering man

In applied to a person, genetic engineering could be used to treat hereditary diseases. However, there is a significant difference between the treatment of the patient himself and the change in the genome of his descendants.

Although on a small scale, genetic engineering is already used to give a chance to get pregnant to women with some varieties of infertility. To do this, use eggs a healthy woman. The child as a result inherits the genotype from one father and two mothers. With the help of genetic engineering, it is possible to obtain descendants with altered appearance, mental and physical ability, character and behavior. In principle, you can create more serious changes, but in the way of such transformations, humanity needs to solve many ethical problems.

Notes

BBC News. news.bbc.co.uk. Verified 2008-04-26

Literature

Singer M., Berg P. genes and genome. - Moscow, 1998.

Stent, Calindar R. Molecular genetics. - Moscow, 1981.

Sambrook J., Fritsch E.F., Maniatis T. Molecular Cloning. - 1989.

Genetic Engineering - This is an area of \u200b\u200bbiotechnology, which includes actions for the restructuring of genotypes. Already today, genetic engineering allows you to include individual genes, thus controlling the activities of organisms, and also to transfer genetic instructions from one body to another, including other types of organisms. As genetics are more familiar to the work of genes and proteins, it becomes more realistic to program the genotype (first of all, human), with more effects reaching any results: such as radiation resistance, the ability to live under water, the ability To the regeneration of damaged bodies and even immortality.

Genetic information. Genetic information (gene) is contained in a cell in chromosomes (in humans of them 46) consisting of DNA molecule and protein packaging, as well as in mitochondria. DNA (deoxyribonucleic acid) is a sequence of nucleotides, each of which contains one of the four nitrogenous. From a functional point of view, DNA consists of a plurality of blocks (nucleotide sequences) that store a certain amount of information - genes.

The gene is a part of the DNA molecule, which contains information on the primary structure of a single protein (one gene is one protein). The combination of all gene genes is its genotype. All organism cells contain the same set of genes, but each of them is implemented by various parts of the stored information. Only those genes are active, which are necessary for the functioning of this cell, therefore, for example, neurons and structurally functional, and biological characteristics differ from liver cells.

The role of proteins in the body. Proteins are the most important molecules in every living organism, the chemical basis of living matter. By definition Engels "Life is a way of existence of protein bodies." Proteins carry out metabolism (transfer of substances in the body) and energy transformations, provide the structural base of tissues, serve as catalysts of chemical reactions, protect organisms from pathogens, transfer messages regulating the body's activities. Chemically proteins are a chain of amino acids, fresh in space in a special way. One of the functions of proteins is the activation of genes. Some genes contain fragments that attract certain proteins. If such proteins are contained in the cell, they join this section of the gene and can allow or disable it to copy it to RNA. The presence or absence of similar regulatory proteins in the cell determines which genes are activated, and therefore, which new proteins are synthesized. It is this regulatory mechanism that determines whether the cell should function as muscular or as a nervous cell or which part of the body should develop in this part of the embryo. If you contribute to the body (plant, microorganism, animal or even a person) new genes, then you can give it a new desired characteristic, which before it never possessed

Genetic engineering originates in 1973, when the genetics Stanley Kokhlen and Herbert Boyer introduced a new gene in the bacterium of the intestinal stick (E. coli). Since 1982, the company, Japan, Great Britain and other countries, produce genetic engineering insulin. The cloned genes of human insulin were introduced into the bacterial cell, where the synthesis of the hormone began, which natural microbial strains never synthesized. About 200 new diagnostic preparations have already been introduced into medical practice, and more than 100 genetic engineering medicinal substances are at the stage of clinical study. Among them, drugs, healing arthrosis, cardiovascular diseases, some tumor processes and, possibly, even AIDS. Among the few hundred genetically engineering companies, 60% work on the production of medicinal and diagnostic preparations.

Genetic engineering in agriculture. By the end of the 1980s, it was possible to successfully introduce new genes in dozens of plant species and animals - to create tobacco plants with luminous leaves, tomatoes, easily carrying frosts, corn, resistant to pesticides. One of the important tasks is to obtain plants that are resistant to viruses, since there are currently there are no other ways to combat viral infections of crops. Introduction to plant cells of the virus shell protein cells makes plants resistant to this virus. Currently, transgenic plants are obtained, capable of resisting more than a dozen different viral infections. Another task is related to the protection of plants from insect pests. The use of insecticides is not quite efficient. In the genetic engineering laboratories of Belgium and the United States, work was successfully carried out on the introduction of Bacillus Thuringiensis genes into the plant cell, allowing to synthesize insecticides of bacterial origin. These genes were introduced into potatoes, tomatoes and cotton cells. Transgenic plants of potato and tomatoes have become resistant to an invincible colorado beetle, cotton plants turned out to be resistant to different insects, including a cotton scoop. The use of genetic engineering has reduced the use of insecticides by 40-60%. Genetic engineers brought transgenic plants with an extended ripening period of fruits. Such tomatoes, for example, can be removed from the bush red, without fear that they overreach during transportation. List of plants to which genetic engineering methods have been successfully applied, is about fifty species, including apple trees, plum, grapes, cabbage, eggplant, cucumber, wheat, soy, rice, rye and many other agricultural plants.

Man's gene therapy

In humans, the technology of genetic engineering was first applied to the treatment of Ashanti de Silva, a four-year-old girl suffering from a heavy form of immunodeficiency. The gene containing instructions for the production of adenosine administration protein (ADA) was damaged. And without protein ADA, white blood cells die, which makes the body defenseless before viruses and bacteria. A working copy of the ADA gene was introduced into Ashanti's blood cells using a modified virus. Cells were able to independently produce the necessary protein. After 6 months, the amount of white cells in the body of the girl rose to a normal level. After that, the region of gene therapy received an impetus to further development. Since the 1990s, hundreds of laboratories have been studying for the use of gene therapy for disease treatment. Today we know that with the help of gene therapy you can treat diabetes, anemia, some types of cancer, Huntington's disease and even purify the arteries. Now there are more than 500 clinical trials of various types of gene therapy. An unfavorable ecological situation and a number of other similar reasons lead to the fact that more and more children are born with serious hereditary defects. Currently, 4,000 hereditary diseases are known, for most of which have not been found effective methods of treatment. Today, it is possible to diagnose many genetic diseases in the embryo or embryo stage. While you can only stop pregnancy at the earliest stage in the case of serious genetic defects, but soon it will be possible to adjust the genetic code, correcting and optimizing the genotype of the future child. This will fully avoid genetic diseases and improve the physical, mental and mental characteristics of children.

Project "Man's Genome". In 1990, the United States was launched in the United States, the purpose of which was to determine the entire genetic year of man. The project in which Russian genetics played an important role was completed in 2003. As a result of the project, 99% of the genome was determined with an accuracy of 99.99% (1 error of 10,000 nucleotides). The completion of the project has already brought practical results, for example, easy to use tests to determine the genetic predisposition to many hereditary diseases. For example, hopes that, due to the expansion of the genome, already by 2006, drugs will have been developed for the treatment of such a dangerous disease as AIDS, by 2009, genes that are associated with malignant neoplasms will be determined, and by 2010-2015 mechanisms will be established The emergence of almost all types of cancer. By 2020, the development of drugs preventing cancer can be completed.

Prospects for control over genes. The development of genetic engineering will make it possible to improve the human genotype. Large-minded tasks that have been demanding today in humanity today require people talented in many industries, perfect and highly developed personalities who have perfect health, the highest physical and mental abilities. Such people can be created by methods of gene, genetic and cellular engineering. These methods will be applicable to both children appearing on the light and for adults. A person will be able to repeatedly strengthen his own abilities, and increase the ability of his children. From an objective point of view, there is nothing bad or not ethical. Already today, many world-famous scientists, such as Watson, one of DNA discovers, suggest that human nonsense, for example, is essentially curable in the future. Genetic causes of disease will be completely eliminated, all people will be completely healthy. Aging will be stopped and no one will have to deal with fading, with a decline of forces, with stiffness. People will become almost immortal - death will become more rare, having ceased to be inevitable. It is known, for example, that one of the reasons for aging is the telomer reduction at each cell division. In the late 1990s, scientists managed to introduce into the cells an open gene, which is responsible for the production of protein telomerase, restoring telomeres, and thereby make them immortal. Of course, individual groups that are not aggravated by the relevant knowledge, but who pursue some personal, ideological or lobbying goals may try to prohibit similar technologies, but as the history of science development shows, it will not be able to do it for a long time.

Genetic engineering has committed a breakthrough in the treatment of cancer. Steven Rosenberg and his colleagues from the American National Cancer Institute (National Cancer Institute) were tried on a number of patients a new method of combating tumors based on the introduction of redesigned immune cells into the organism. Remember, as recently, scientists managed to "train" immune systems with mice effectively combating cancer tumors by simple transplantation of white blood cells, backed from individuals, for natural reasons to cancer immune (after all, there are such organisms)? Now a similar method of treatment of cancer is tested on humans. At first, the authors of the work took immune cells - T-lymphocytes - in a person who, by virtue of their natural features, was able to successfully "remove" melanoma. Scientists have determined the genes responsible for the operation of the receptor recognizing cancer cells and ran this gene. They then took T-lymphocytes in several patients with melanoma and with the help of retrovirus introduced an artificial, cloned gene in them. The patients then suffered a chemotherapy procedure, after which their immune systems were weakened, with extremely small number of surviving immune cells. Here, this patients returned their own T-cells, started earlier, but now - with the new genome implemented in them (more in the press release of the institute). After a month in 15 patients out of 17, these new cells not only survived, But amounted to from 9% to 56% of the total "population" of T-lymphocytes in the body. But the main surprise - after 18 months after treatment, two patients completely got rid of cancer, and also demonstrated a high level of T cells in the blood. one patient for cancer education There were two, one of which was completely destroyed, and the second - decreased by 89% (after which it was removed by surgical entry), and the second patient was one tumor, which "scattered". Rosenberg notes that "for the first time gene manipulations led to a tumor regression." "We can now take normal lymphocytes in patients and modify them into lymphocytes that react to cancer cells," said the scientist, which intends to continue the study. He wants to know how genetically modified cells will survive in the body for more period, how this therapy will work in a complex with other cancer treatment methods, as it can help when dealing with other types of cancers (other genes encoding the construction of others will operate receptors). In general, there are still a lot of questions. If you can move a little, then you can also say about the ultrasonic ablation of HIFU therapy. The leader in this area is the doctors of the PRC. Its technology lies in the burning of cancer cells by ultrasound, at a temperature of 100 degrees Celsius tumor literally melts. The leader in the production of specialized equipment is the Beijing company Haifuning Hifu Technology, which, together with the American company, General Electric has created a fully computerized machine with a controlled temperature mode - FEP by 02.

Literature:

1. Singer M., Berg P. genes and genome. - Moscow, 1998.
2. Stent, Calindar R. Molecular genetics. - Moscow,
3. Sambrook J., Fritsch E.F., Maniatis T. Molecular Cloning. -
4. Patrushev L. I. Artificial genetic systems. - M.: Science, 2004.
5. Schelkunov S. N. Genetic engineering. - Novosibirsk: Sib. unison Publishing house, 2008.
6. Freedom of speech (newspaper, materials from number 4 (348) 2.02.2012)

Genetic engineering

Modern biology is fundamentally different from traditional biology not only greater depth of developing cognitive ideas, but also a closer communication with the life of society, with Pracolika. It can be said that in our time, biology has become a means of transforming a living world in order to meet the material needs of society. This conclusion is illustrated primarily by the close relationship of biology with biotechnology, which has become the most important area of \u200b\u200bmaterial production, an equal partner of mechanical and chemical technologies created by a person, as well as medicine.

Since its inception, biology and biotechnology have always developed jointly, and from the very beginning, biology was the scientific basis of biotechnology. However, a long time lack of own data did not allow biology to provide a very large influence on biotechnology. The position has changed dramatically with the creation in the second half of the XX century. genetic engineering methodologies,under which the genetic manipulation is understood to design the new and reconstruction of existing genotypes. As a methodological achievement, genetic engineering did not lead to the breakdown of the prevailing ideas about biological phenomena, did not affect the main provisions of biology, just as radio astronomy did not lay the main provisions of astrophysics, the establishment of a "mechanical equivalent of heat" did not lead to a change in the laws of thermal conductivity, and the proof The atomistic theory of the substance is not a measure of the ratios of thermodynamics, hydrodynamics and the theory of elasticity (A.A. Baev).

Nevertheless, genetic engineering has opened a new era in biology for the reason that new opportunities have appeared for pronounced biological phenomena in order to further characterize the forms of living matter existence, more efficiently studying the structure and functions of genes at the molecular level, understanding of subtle work mechanisms genetic apparatus. The successes of genetic engineering mean a coup in modern

natural science. They determine the criteria for the value of modern ideas about the structural and functional features of the molecular and cellular levels of living matter. Modern data on lives have a giant cognitive importance, because they provide an understanding of one of the most important parties to the organic world and thereby make an invaluable contribution to the creation of a scientific picture of the world. Thus, dramatically expanding its cognitive base, biology through genetic engineering also had the leading effect on the rise of biotechnology.

Genetic engineering creates grounds on the way of knowledge of the methods and ways to "design" new or improving existing organisms, giving them greater economic value and the ability of a sharp increase in the productivity of biotechnological processes. However, genetic engineering has created new horizons and medicine for the diagnosis and treatment of many diseases, both non-treating and hereditary. She opened new ways in search of new drugs and materials used in medicine. Genetic engineering and biotechnology stimulated the development of bionanotechnology methods.

As part of genetic engineering distinguish gennaand cellularengineering. Under genetic engineering, manipulation is understood in order to create recombinant DNA molecules. Often this methodology is called molecular cloning, cloning of genes, recombinant DNA technologies or simply genetic manipulations. It is important to emphasize that the object of genetic engineering is DNA molecules, individual genes. On the contrary, under cell engineering, genetic manipulations with isolated individual cells or groups of plant cells and animals are understood.

Genetic engineering and its tools

Genital engineering is a combination of various experimental techniques (techniques), providing construction (reconstruction), cloning DNA molecules and genes with specified objectives.

Methods of genetic engineering are used in a certain sequence (Fig. 127), and there are several stages in

a typical genetic engineering experiment aimed at cloning any gene, namely:

1. Isolation of DNA plasmidium from the cells of the body of interest (source) and the allocation of the DNA vector.

2. Cutting (restriction) of the DNA of the original organism on fragments containing genes of interest, using one of the restrictasis enzymes and the selection of these genes from the restriction mixture. Simultaneously cut (rest) vector DNA, turning it from the ring structure into linear.

3. Fit the DNA (gene) of the DNA segment of the vector in order to obtain hybrid DNA molecules.

4. Introduction of recombinant DNA molecules by transformation into any other organism, for example, E. coli.or somatic cells.

5. Sewing bacteria in which hybrid DNA molecules were injected to nutrient media, allowing the growth of only cells containing hybrid DNA molecules.

6. Identification of colonies consisting of bacteria containing hybrid DNA molecules.

7. Isolation of cloned DNA (cloned genes) and its characteristic, including sequencing nitrogenous bases in the cloned DNA fragment.

Fig. 127.Sequential stages of a genetic engineering experiment

During the evolution of bacteria, the ability to synthesize the so-called restricting enzymes (endonucleases), which became part of the cellular (bacterial) system of restriction. The bacteria system restriction-modifications are an intracellular immune system of protection against alien DNA. Unlike the highest organisms, whose recognition and destruction of viruses, bacteria and other pathogens occurs extracellularly, in bacteria protection against alien DNA (DNA of plants and animals, in the body of which they dwell) occurs intracellularly, i.e. Then, when alien DNA penetrates the cytoplasm of bacteria. In order to protect the bacteria during the evolution, the ability to "mark" their own DNA was also developed by methylate bases on certain sequences. For the same reason, alien DNA due to the lack of methyl groups on the same sequences, it melts (cut) into fragments by different bacterial restrictions, and then degraded by bacterial exonucleases to zerootides. It can be said that thus bacteria protected themselves from DNA of plants and animals, in the body of which they live temporarily (as pathogens) or constantly (as saprophytes).

Restrictases were first highlighted from E. coli.in 1968 it turned out that they are able to cut (melted) DNA molecules on different sites (places) restriction. These enzymes got the name of the endonuclease class I. Then, the bacteria were found by class II endonucleases, which recognize in alien DNA restriction sites specifically and on these sites also carry out restriction. It was the enzymes of this class who began to use in a genetic engineering. At the same time, class III enzymes were discovered, which are floating DNA next to recognition sites, but these enzymes do not matter in genetic engineering.

The effect of the restriction-modification system "rationalizes" the so-called palindromic (recognizing) sequences of nitrogen bases, which are the restriction sites of DNA. Palindromic sequences are the base sequences that are equally read back and forth, such as the sequence of letters. radar.Since the DNA circuits have an anti-parallel direction, it is believed that the sequence is palindromic if it is identical when it is read in the direction from 5 "- to 3" -concu on the top and on the lower chain from 3 "- to 5" -con, namely :

Palindroma can be any size, but most of those palindromes that are used as recognition sites with restrictions, consist of 4, 5, 6 and less than 8 grounds.

Restractase is an absolutely necessary tool in genetic engineering to cut fragments of interest (genes) from large DNA molecules. Since more than 100 restriction enzymes are known, this allows the selection of restrictions and selective cutting of fragments from source DNA.

A wonderful feature of the restrictasis is that they produce cuts of molecules into several fragments (restrictions) DNA of the ledges, as a result of which in the generated ends one chain is longer than another, forming a peculiar tail. Such ends (tails) were called "sticky" ends, as they are capable of self-checking.

Consider the results of restriction on the example of one of the most famous restrictions. Eco Ri.from the system restriction-modification E. soy.Instead of melting DNA in the center of the palindromic sequence of recognition, this enzyme melts DNA for the trains of the center and produces 4 self-checking ("sticky") end consisting of different number of nucleotides, namely:

These "sticky" ends in genetically engineering experiments are useful for the reason that they can be reunited complementary at low temperatures, which allows effective closure of DNA fragments.

Recognition sites and melting sites in the case of other restrictions have another content, namely:

Following the restriction of DNA from the restriction mixture, restriction DNA fragments (DNA restrictions) are disticted, which are then required to combine with the vector. To highlight DNCTRIKTS, resort to electrophoresis, since with the help of this method, restricciated DNA is very easily fractioning due to the size of the resorts-restrictions and constant relationships electric charges. Fragments in the electric field are migrated during electrophoresis at a frequency depending on their dimensions (mass). The more (longer) a fragment, the slower he migrates in an electric field. The material in which electrophoresis is carried out is uncharged agrozen or polyacrylamide. To identify fragments, ethidium bromide is used, which paints fragments, which leads to their easier detection.

The effectiveness of electrophoresis is very high, since it can be separated by fragments, the dimensions of which are composed of 2 to 50,000 bases.

After electrophoresis, fragments from agarose are isolated using different methods. Based on the results of the comparison of the size

the restrictions of the same DNA obtained using different restrictions are building restriction maps on which the restriction sites of each of the used restrictions are shown. In practical terms, restriction cards allow you to determine not only the size of restrictions, but also to find out the location in the DNA loci molecules of those or other genes.

Since heterogeneous DNA is synthesized during transcription, heterogeneous DNA, corrected by processing, then in genetic engineering, complementary DNA (cDNA) is usually used, which is obtained using MRNA as a matrix, on which the reverse transcriptase synthesizes single-stranded DNA (cDNA), which is a copy of MRNA. Subsequently, these single-stranded DNAs are converted into two-stranded DNA. It is believed that the cDNA contains continuous nucleotide sequences (transcribed and translated). It is cDNA that is used for restriction.

Selected after electrophoresis of agarose gels DNA fragments (restrictions) can be pre-subjected to seven valves, i.e. Determine the nucleotide sequence in them. To do this, serve chemical and enzymatic methods of sequencing. The chemical method is based on obtaining labeled by radioactive phosphorus (32 p) fragments and removal from these fragments of one of the grounds, followed by the results of the results of the radioautographics of gels containing these fragments. The enzymatic method is based on the fact that nucleotide is introduced into the end of the analyzed fragment, then used in the synthesis of different fragments in vitroanalyzed by the nucleotide sequence of electrophorestically. To study specific nucleotide sequences in the DNA molecule use

also hybridization of DNA DNA, RNA RNA, DNA RNA, nodern

and sauzer-blottings.

Genetic vectors. The DNA segment (gene), which is intended for molecular cloning, must have the ability to replicate when transferred it to the bacterial cell, i.e. To be replicom. However, he does not possess such ability. Therefore, in order to ensure the transfer and detection of cloned genes in cells, they are combined with the so-called genetic vectors. The latter must have at least two properties. First, vectors must be capable of replication

in cells, and in several ends. Secondly, they must provide the possibility of cell selection containing the vector, i.e. Put the marker on which the cell counterfeiting containing the vector together with the cloned genome (recombinant DNA molecules). Such requirements correspond to plasmids and phages. Plasmids are good vectors for the reason that they are replicances and may contain a resistance genes to any antibiotic, which allows the selection of bacteria to resistance to this antibiotic and, therefore, the easy detection of recombinant DNA molecules

(Fig. 128).

Fig. 128.Vector pbl.

Since there are no natural plasmid vectors, then all the plasmid vectors known to date have been constructed artificially. The source material for the creation of a number of genetic vectors served as R-plasmids, in which, with the help of restrictions, unnecessary DNA sequences were removed, including those on which multiple restriction sites were located. This deletion was determined by the fact that the plasmid vector should have only one recognition site for one restrictase, and this site should lie in a functionally insignificant area of \u200b\u200bthe plasmid genome. For example, the plasmid vector PBR 322, which has ampicillin resistance genes and tetracycline, which makes it very convenient

for breeding bacteria containing a cloned DNA segment, has single restriction sites for more than 20 restriction enzymes, including such known restrictions as ECO RI, Hind III, PST I, PVA II and SAL I.

Fagovy vectors also have a number of benefits. They may include larger (longer) cloned DNA fragments compared to plasma vectors. Further, the transfer of the fags of a cloned fragment into cells as a result of infection with the latter is more efficient than the transformation of DNA. Finally, phage vectors allow more efficient screening (recognition) on the surface of the agar colonies containing cells carrying the cloned gene. Many phage vectors are designed on the basis of the Phage Lambda.

In addition to phage, other viral vectors are used, designed on the basis of herpes virus, as well as vectors designed on the basis of yeast DNA.

If the cloning of genes is carried out using mammalian or plant cells, then the requirements for vectors are the same as in the case of cloning in bacterial cells.

Construction of recombinant DNA molecules. Direct design of recombinant DNA molecules follows after restrictions of DNA studied and vector DNA are obtained. It consists in closure of segments-restrictions of the studied DNA with the restriction of vector DNA, which as a result of restriction turns from the ring in linear DNA.

To close the fragments of the studied DNA with DNA vector, use DNA ligase (Fig. 129). Ligation will be successful if the closed structures have z "-hydroxyl and 5" -phoscope groups and if these groups are located appropriately with respect to one other. Fragments are combined through their "sticky" ends as a result of self-checking. At high concentrations of fragments, the latter from time to time becomes the correct position (opposite each other). Many restrictases, such as ECO RI, produce "sticky" ends consisting of four bases. The process of ligation of the "sticky" ends consisting of four bases occurs under reduced temperature (up to 12? C).

Fig. 129.DNA ligation

If during restrictions, fragments are formed without "sticky" ends, they are "violently" converted into molecules with "sticky" ends using a transferase enzyme. This enzyme adds a nucleotide to 3 "DNA-A-tail on one fragment. A poly-tail can be added on another - poly-t-tail. To generate any desired DNA ends, a polymerase chain reaction (PCR) is also used. PCR principle is based on On denaturations isolated from DNA cells and "annealing", it was added to the renaturizing chains of DNA oligonucleotides, consisting of 15-20 nucleotides each. These oligonucleotides must be complementary to sequences in chains, separated by distances in 50-2000 nucleotides. Being a "seed" for DNA synthesis in vitrothey allow DNA polymerase to copy those sites that are between "seeds". This copy gives a large number of copies of the DNA fragment under study.

Introduction of recombinant DNA molecules in cells. After the closure of the DNA fragment of interest (gene) with a genetic vector with DNA ligases, the formed recombinant molecules are introduced into the cells to achieve their replication (due to the genetic vector) and increase the number of copies. The most popular method of introducing recombinant DNA molecules in the cells, in which the vector is plasmid, is the transformation E. coli.For this purpose, bacterial cells are pre-treated with calcium or rubidium (ions) for

so that they become "competent" in the perception of recombinant DNA. To increase the frequency of DNA penetration into cells, the electroporation method consisting in brief exposure of cells in an intense electric field is used. This treatment creates cavities in cell membranes, which contributes to better perception of DNA cells. After administration of recombinant DNA molecules in bacteria, the latter are sown on MPa (meat-pepton agar), enriched with antibiotics for selecting the desired cells, i.e. Cells containing recombinant DNA molecules. The frequency of transformation is low. Usually one transformant occurs by 10 5 of the sinky cells. If the vector is a phage, then resort to transfection of cells (bacteria or yeast) by phage. As for the somatic cells of animals, their transfection is carried out by DNA in the presence of chemicals that facilitate the passage of DNA through plasma membranes. Direct microengetations of DNA in Ovilosites are also possible, in cultured somatic cells and mammalian embryos.

The most important point associated with molecular cloning is the search for a method that allows you to establish whether the cloned fragment is valid in the vector and together with the vector, forming a recombinant DNA molecule, entered the cells. If we are talking about bacterial cells, then one of the ways is based on the registration of inserting inactivation of plasmid (vector) resistance gene. For example, in the plasmid vector PBR 322, determining the ampicillin and tetracycline resistance, the uniform site for the PST I restriction is located in the locus occupying the ampicillin resistance genome. PST I-melting on this site generates "sticky" ends, allowing ligation of the cloned fragment with vector DNA. However, at the same time plasmid (vector) ampicillin resistance gene is inactivated, while the tetracycling resistance gene on the vector remains intact. It is the tetracycling resistance gene and is used for cell selection transformed by recombinant DNA molecules. This makes sure that the cells of the grown colonies on a tetracycline medium truly contain recombinant DNA molecules, they are checked with the help of the so-called "spot test" on a pair of cups with a dense medium, one of which contains ampicillin, while the other is deprived of this antibiotic. Cloned DNA are located

only in transformants resistant to tetracycline. As for transformants, resistant simultaneously to ampicillin and tetracycline (ARTS), then they contain plasmid (vector) molecules that spontaneously purchased a ring form without inclusion in them alien (cloned) DNA.

Another way to detect the insertion of alien (cloned) fragments to the plasmid vector is based on the use of a vector containing β-galactosidase gene. The insertion of alien DNA in this gene inevitably inactivates the synthesis of β-galactosidase, which can be detected by sowing transformed cells on a medium that contains substrates β-galactosidase. This medium allows the selection of colored cell colonies. There are other methods.

As already noted, restriction linear fragments of vector DNA are capable of restoring the ring structure without inclusion in them cloned segments. To reduce the frequency of spontaneous formation of such ring molecules of vector DNA, restrictions of vector DNA are processed by phosphatase. As a result, the formation of annular DNA molecules becomes impossible, since there will be no ends 5 "-ro 4, necessary for the action of ligase.

A combination of colonial transformants grown on a selective medium is a set of cells containing clones of different fragments (genes) of a cloned genomic or cDNA. The collection of these clones form the so-called DNA libraries widely used in genetic engineering works.

The final staging of gene cloning is the allocation and study of cloned DNA, including sequencing. Perspective strains of bacteria or somatic cells containing recombinant DNA molecules that control the synthesis of proteins of interests that have commercial value are transmitted to industry.

Cellular engineering

As noted at the beginning of chapter, cell engineering is called genetic manipulations with isolated cells of animals and plants. These manipulations often carry out in vitroand the main goal they have to obtain the genotypes of these organisms with the specified properties, primarily economical useful. As regards-

human, cell engineering turned out to be applicable to sex cells.

The prerequisite for the development of cellular engineering in humans and animals was the development of methods for cultivating their homogenic cells on artificial nutrient media, as well as obtaining hybrids of somatic cells, including interspecific hybrids. In turn, progress in the cultivation of somatic cells had an impact on the study of sex cells and fertilization in humans and animals. Starting from the 60s. Xx in. In several laboratories of the world, numerous experiments on transplanting nuclei of somatic cells in the egg cell, artificially deprived of the cores were performed. The results of these experiments were often contradictory, but in general they led to the opening of the ability of cell cores to ensure the normal development of the egg (see ch. IV).

Based on the results of studying the development of fertilized eggs in the 60s. XX century Studies were also started to clarify the possibility of fertilizing eggs outside the mother's body. Very rapidly, these studies led to the discovery of the possibility of fertilizing egg sperm in the tube and the further development of the embryos formed in an implantation in a woman's umbrella. Further improvement of methods developed in this area led to the fact that the birth of the "pierces" of children became a reality. Already by 1981, 12 children were born in the world, the life of which was given in the laboratory, in a test tube. Currently, this section of cell engineering was widely distributed, and the number of "probiors" children is already tens of thousands (Fig. 130). In Russia, work on obtaining "probiors" children were started only in 1986

In 1993, a technique was developed for obtaining monosigital twins in vitro.by separating embryos on blastological and rearing the last to 32 cells, after which they could be implanted in a woman's uterus.

Under the influence of the results associated with obtaining "pierced" children, the animals also developed a technology called transplantationembryos. It is associated with the development of a method for induction of polyovulation, methods of artificial desolation of egg cells and implantation of embryos in the organism of animals - receiving mothers. The essence of this technology is reduced to the following

. Hormones are introduced highly productive cow, as a result of which polysulation comes in maturation of 10-20 cells at once. Then the egg cells are artificially fertilized by male sex cells in the ovage. On the 7-8th day, embryos were washed out of the uterus and transplan into the uterus to other cows (receiving mothers), which then give life to twin calves. The calves inherit the genetic status of their authentic parents.

Fig. 130."Proberi" children

Another area of \u200b\u200bcell engineering in animals is the creation of transgenic animals. The easiest way to obtain such animals is to introduce in the egg cells of the original animals of linear DNA molecules. Animals developed from the ok fertilized in this way will contain a copy of the entered gene in one of its chromosomes and, in addition, they will transmit this gene inheritance. A more complex method of obtaining transgenic animals is designed on mice differing in the color of the coarse cover, and comes down to the following. Initially, the organism of a pregnant gray mouse is extracted by four-day embryos and crushed them into individual cells. Then the kernels are removed from embryonic cells, they carry them into the eggs of black mice, pre-devoid of nuclei. Black mice eggs containing other people's kernels are placed in test tubes

with nutrient solution for further development. Ukrainian embryos developed from the egg mice are implanted in the uterus of white mice. Thus, in these experiments, it was possible to obtain a clone of mice with gray colorful cohesive cover, i.e. Close the embryonic cells with specified properties. In Chapter IV, we considered the results of fertilization of artificially deprived of the cores of the sheep with a nuclear material of somatic cells of animals of the same species. In particular, the kernels were removed from the egg cells, and then the kernels of somatic cells (embryonic, fruit or adult animal cells) were injected into such eggs (embryonic, fruit or cells of adult animals), after which the eggs were fertilized in this way were injected into the uterine of adult sheep. The born lambs turned out to be an identical oxycedonor. An example is a sheep dolly. Clone calves, mice, rabbits, cats, mules and other animals are also obtained. Such constructing of transgenic animals is a direct path of cloning animals with economically useful features, including individuals of a particular floor.

Transgenic animals are also obtained using the source material belonging to different types. In particular, a method of transmitting a gene controlling growth hormone, from rats in mice eggs, as well as a method for combining sheep blastomers with goat blastomers, which led to the occurrence of hybrid animals (tack). These experiments indicate the possibility of overcoming species incompatibility in the earliest stages of development. Especially tempting prospects are opened (if species incompatibility will be completely overcome) on the way of the fertilization of egg cells of one type of the nuclei of somatic cells of another species. We are talking about the real perspective of creating economic hybrids of animals, which cannot be obtained by crosses.

It should be noted that nuclear transplantations are not yet very effective. Experiments made on amphibious and mammals, generally showed that their effectiveness is small, and it depends on the incompatibility between donor nuclei and recipient oocytes. In addition, the obstacle on the way to successes is also formed chromosomal aberrations in transplanted nuclei during further development, which are accompanied by the death of transgenic animals.

At the stake of work on the study of hybridization of cells and immunological studies, a problem arose with obtaining and studying the so-called monoclonal antibodies. As noted above, antibodies produced by the body in response to the introduction of antigen (bacteria, viruses, erythrocytes, etc.) are proteins called immunoglobulins and components of the fundamental part of the body's protective system against disease pathogens. But any alien body introduced into the organism is a mixture of different antigens that will excite the products of different antibodies. For example, human erythrocytes possess antigens not only for blood groups A (II) and in (III), but also by many other antigens, including the Rh. Further, the cell wall proteins of bacteria or a capexide of viruses can also act as different antigens causing the formation of different antibodies. At the same time, lymphoid cells of the body's immune system are usually represented by clones. It means that even for this reason in the serum of immunized animals, antibodies are always a mixture consisting of antibodies produced by cells of different clones. Meanwhile, antibodies of only one type are needed for practical needs, i.e. So-called monospecific serums containing antibodies of only one type or, as they are called, monoclonal antibodies.

In search of methods for obtaining monoclonal antibodies by Swiss researchers in 1975, a method of hybridization was opened between mice lymphocytes immunized with a particular antigen, and cultivated bone marrow tumor cells. Such hybrids were called "Hybrid". From the "lymphocytic" part represented by the lymphocyte of one clone, a single hybridoma inherit the ability to cause the formation of the necessary antibodies, with the same type, and due to the "tumor (millet) part it becomes capable of, like all tumor cells, is infinitely known to unlock on artificial Nutrient media giving a numerous hybrid population. In fig. 131 shows a diagram of isolating cell lines synthesizing monoclonal antibodies. The lines of mouse cells that synthesize monoclonal antibodies are isolated by fusion of myeloma cells with lymphocytes from a mouse spleen immunized in five days before

the desired antigen. The fusion of cells reaches them with mixing them in the presence of polyethylene glycol, which induces the fusion of cell membranes, and then in extinguishing them to the nutrient medium, which allows the growth and reproduction of only hybrid cells (hybrid). The reproduction of a hybrid is carried out in a liquid medium, where they grow further and secrete antibodies into the culture fluid, with only one type, besides in unlimited quantities. These antibodies were called monoclonal. To increase the frequency of antibody formation, resort to hybrid cloning, i.e. To the selection of individual colonies hybridoma capable of causing the formation of the greatest number of antibodies of the desired type. Monoclonal antibodies have found wide use in medicine for the diagnosis and treatment of a number of diseases. At the same time, the most important advantage of monoclonal technology is that it can be obtained antibodies against materials that cannot be cleaned. On the contrary, it is possible to obtain monoclonal antibodies against cellular (plasma) membranes of animal neurons. For this, mice are immunized by the dedicated membranes of neurons, after which their spiley lymphocytes are combined with myeloma cells, and then come, as described above.

Fig. 131. Obtaining monoclonal antibodies

Genetic Engineering and Medicine

Genetic engineering was very promising for medicine, primarily in creating new technologies for obtaining physiologically active proteins used as drugs (insulin, somatostatin, interferon, somatotropin, etc.).

Insulin is used to treat patients with diabetes, which is in third place (after heart disease and cancer) at the frequency of deaths caused. The global need of insulin is several tens of kilograms. Traditionally, it is obtained from pancreatic glands of pigs and cows, but the hormones of these animals are slightly different from human insulin. Insulin pigs varies on one amino acid, and the cow - in three. It is believed that animal insulin often causes side effects. Although the chemical synthesis of insulin has long been carried out, but so far the industrial hormone production remained very expensive. Now cheap insulin is obtained with a genetic engineering method by chemical-enzymatic synthesis of insulin gene, followed by the introduction of this gene in the intestinal wand, which then synthesizes the hormone. Such insulin is more "biodegradable", since it is chemically identical to insulin produced by human pancreas cells.

Interferons - proteins synthesized by cells mainly in response to the infection of the organism by viruses. Interferons are characterized by species specificity. For example, a person has three groups of interferons produced by various cells under the control of the respective genes. Interest in interferons is determined by the fact that they are widely used in clinical practice for the treatment of many human diseases, especially viral.

Having large sizes, interferon molecules are little accessible to synthesis. Therefore, most interferons are now obtained from human blood, but the output with this method of obtaining a small one. Meanwhile, the need for interferon is extremely large. This set the task to find an effective method of production of interferon in industrial quantities. Genetic engineering underlies the modern production of "bacterial" interferon.

The influence of genetic engineering on the technology of those medicinal substances that have long been created by biological technology has increased. Back in the 40-50s. XX century was created

the biological industry for the production of antibiotics, which constitute the most efficient part of the medicine arsenal of modern medicine. However, in recent years there has been a significant increase in the drug sustainability of bacteria, especially antibiotics. The reason is to be widely distributed in the microbial world plasmid determining the drug stability of bacteria. That is why many famous previous antibiotics have lost their former efficacy. The only way to overcoming the resistance of bacteria to antibiotics is the search for new antibiotics. According to experts, about 300 new antibiotics annually create in the world. However, most of them are either ineffective or toxic. In practice, only a few antibiotics are introduced every year, which causes not only to maintain, but also to increase the power of the antibiotic industry based on genetic engineering development.

The main tasks of genetic engineering in those drugs in which microorganisms are produced by drugs are determined by the need for genetic engineering reconstruction of the latter in order to increase their activity. At the same

the time began to implement the idea of \u200b\u200bcreating medicines in the form of small molecules, which contributes to their greater efficiency.

Immune biotechnology is related to the production of primarily new generation vaccines for the prevention of human infectious diseases and animals. The first commercial products created by genetic engineering were vaccines against hepatitis people, animal floors and some others. An extremely important direction in this area is associated with the production of monoclonal antibodies, reagents necessary for the diagnosis of pathogens of the disease, as well as for cleaning hormones, vitamins, proteins of various nature (enzymes, toxins, etc.).

A significant practical interest is the method of obtaining artificial hemoglobin by administering hemoglobin genes in tobacco plants, where the α- and β-chains of globin are produced under the control of these genes, which are combined into hemoglobin. Synthesized in the cells of tobacco plants hemoglobin is fully functional (binds oxygen). Cellular engineering in the application to a person is connected not only with the solution of the fundamental problems of human biology, but also with overcoming primarily female infertility. Since the frequency of positive cases of implantation in the Embryption Women's Make in vitrois small, then obtaining monosigital twins in vitro.it also matters, as the possibilities of repeated implants increase due to "spare" embryos. Of particular interest are the prospects for the use of stem cells as a source of cell replacement and tissues in the treatment of diseases such as diabetes, damage to the spinal cord, heart pain, ostesharthritis, Parkinson's disease. But to implement these perspectives, an in-depth study of stem cell biology is necessary.

In the use of genetic engineering in relation to the problems of medicine, the task of developing genetically engineering methods of radical treatment of hereditary diseases, which, unfortunately, has not yet been treated with existing methods. The content of this task is to develop methods of correction (normalization) of mutations, the result of which are hereditary diseases, and in ensuring the transfer of "corrections" by inheritance. It is believed that the successful development of genetically engineering methods for the treatment of hereditary diseases will be

promote data on the human genome obtained as a result of the implementation of the International Scientific Program "Man's Genome".

Environmental problems of genetic engineering

Raising biotechnology to a new level, genetic engineering also found the application in developing methods for determining and eliminating environmental pollution. In particular, bacteria strains are constructed, which are peculiar indicators of mutagenic activity of chemical pollution. On the other hand, the strains of bacteria containing plasmids, under the control of which the synthesis of enzymes occur, capable of destroying many chemical compounds of habitat. In particular, some plasmid-containing bacteria are able to decompose to harmless compounds of oil and petroleum products that have found themselves as a result of various accidents or other adverse causes.

However, genetic engineering is the transformation of a genetic material, which is absent in nature. Consequently, genetic engineering products are absolutely new products that do not exist in nature. Therefore, it in itself due to the unknown of its products is dangerous both for nature and habitat and for personnel working in laboratories, which use methods of genetic engineering or work with structures created during genetic engineering works.

Since the possibilities of cloning genes are endless, then at the very beginning of these studies among scientists there have been questions about the nature of the organisms created. At the same time, assumptions were made about a number of unwanted consequences of this methodology, and these assumptions found support and among the general public. In particular, disagrees appeared on the properties of bacteria that received animal genes in genetically engineering experiments. For example, whether bacteria retain E. coli.its species belonging because of the content of animal genes introduced in them (for example, insulin gene) or should they be considered a new type? Further, how long there are such bacteria, in which environmental niches they can

exist? But the most important thing was to consist in the appearance of concerns that in the course of production and manipulations with recombinant DNA molecules, genetic structures with properties, unforeseen and dangerous human health can be created for the historically established ecological equilibrium. At the same time, calls for moratorium on genetic engineering began. These appeals caused an international resonance and led to the International Conference, which took place in 1975 in the United States and on which the possible consequences of research in this area were widely discussed. Then in countries where genetic engineering began to develop, rules for working with recombinant DNA molecules were developed. These rules are aimed at excluding entering the habitat of the products of genetically engineering laboratories.

Another aspect of the undesirable consequences of genetically engineering works is associated with the danger to the health of staff working in laboratories, which use methods of genetic engineering, since phenol, ethidium bromide, UV radiation, which are harmful to health, are used in such laboratories. In addition, in these laboratories, there is a possibility of infection with bacteria containing recombinant DNA molecules that control unwanted properties, such as medicinal resistance of bacteria. These and other points determine the need to increase safety in genetic engineering works.

Finally, the hazard problems of genetically modified products (genetically changed tomatoes, potatoes, corn, soybeans), as well as products such as bread, pasta, candy, ice cream, cheese, vegetable oil, meat products, cheese, vegetable oil, meat products, which are in some countries, especially in the United States, gained widespread. For 12,000 years of agriculture, a person used natural origin products. Therefore, it is assumed that with genetically modified food in the human body, new toxins, allergens, bacteria, carcinogens, will fall, which will lead to completely new diseases of future generations. In this regard, the question arises of a truly scientific assessment of genetically modified food.

ISSUES FOR DISCUSSION

1. What do you understand under gene, cell and genetic engineering? Is there a difference between these concepts and molecular cloning?

2. What is the progressiveness of genetic engineering compared to other methods used in biology?

3. List the main "tools" of genetic engineering.

4. What are restrictase enzymes, what are their properties and their role in genetic engineering?

5. Are all restrictions form "sticky" ends of the studied DNA and does the structure of the "sticky" ends depend on the type of restriction?

6. Give the definition of genetic vectors. Are there natural vectors?

7. How do genetic vectors get in laboratory conditions? What biological objects are the source material to obtain vectors?

8. What is the limiting length of the sequences of nitrogenous bases of DNA, which can still be engaged in the genetic vector? Are Vectors via "Power"?

9. Describe the properties of DNA ligase and determine its role in genetic engineering.

10. How are the cloned DNA segment (gene) with a genetic vector?

11. What is the incidence of recombinant DNA molecules in bacterial cells?

12. In what principle is the selection of bacterial cells containing recombinant DNA molecules? Bring one example of such a selection.

14. Many bacteria strains have the same enzymes, almost equally providing their metabolism. Meanwhile, the nucleotide specificity of restriction systems-modification of bacteria is different. Can you explain this phenomenon?

15. Why DNA sequences representing restriction detection sites cannot contain more than eight base pairs?

16. How many times the sequence of the GHRC, recognizable by the restriction age of Na III, will occur in the DNA segment of 50,000 base pairs with 30-, 50- and 70 percent content of Hz?

17. Restractases BAM Hi and BGL I float the sequences of Gatz and T Gatza, respectively. Is it possible to include in BAM HI site DNA fragments produced by BGL I-restriction? If so, why? If the plasmid used (vector) contains one site for restriction BGL I, then on which nutrient medium you can carry out the selection of bacteria, this plasmid?

18. Calculate the frequency of transformation of bacteria per molecule of DNA, if 5-10 5 transformants are formed by 5000 plasmid base pairs?

19. Is it possible to clone a 0-point DNA replication E. coli.and if so, how?

20. Is it possible to determine how much DNA molecules need to transform one cell E. coli?

21. Is it possible to determine the site of splicing on mRNA using a polymerase chain reaction?

22. How can a polymerase chain reaction be used in order to enter the desired restriction site in the DNA fragment of the DNA intended for cloning?

23. Name the methods of cellular engineering in the use of animals. What is the economic value of animals obtained by these methods?

24. Give the definitions of "transgenic plants" and "transgenic animals". Do the transgenic organisms preserve their species affiliation or can they be considered organisms of new species?

25. What is hybridomas and monoclonal antibodies? How do they get them?

26. Can cell engineering applicable to person?

27. Suppose that the injection of alien DNA in the mouse egg and implantation is fertilized in such a way of an egg to the body of the mouse ended with its pregnancy and birth, mice containing copies of injected DNA in the genome. However, the mice were mosaic, i.e. Some of their cells contain copies of injected DNA, others are deprived of this DNA. Can you explain the nature of this phenomenon?

28. Do you consider genetically dangerous food prepared from genetically modified products?

29. Does scientific expertise of genetically modified foods need?

Cognition is determined by the fact that we are approved as truth.

P.A. Florensky, 1923.

(DNA and RNA) and genetics of microorganisms. It is engaged in deciphering the structure, synthesis of chemical or biochemical, cloning, inserting isolated or newly synthesized in organisms in order to aimed changes in their hereditary properties. Genetic engineering exercise a century-old dream of humanity - management.

Two discoveries made it possible to create genetic engineering. The first of them is the discovery of specific - named with restrictions. Restractations are torn, cut the sequence of nucleotides into DNA, but not where it fell, but only in those places where there is a combination of certain nucleotides, recognizable only by this restriction. These "smart" are isolated from microorganisms that they protect against someone else's genetic information (for example, from DNA). With the help of restrictions, it is possible to be obtained by the same part of the DNA part, for example, include a sequence of nucleotides encoding a certain one. Such may be insulin necessary for the treatment of diabetes, human, or used to treat viral diseases.

It is important for genetic engineering and the other - ligase, "sewing" DNA segments one to another. With it, it is possible, mixing in the tube solutions of different cut (restricted) DNA molecules, sew them into one, i.e. to connect one sequence on the other.

The second discovery underlying genetic engineering is generated in genetic elements. These are annular DNA molecules relative to small length (no more than 100 thousand nucleotide pairs). They are called . It is possible to originate from the so-called moderate phages (see) - not killing bacterial, but transmitted from generation to generation. and moderates can be transmitted from K, and included in their ring DNA, may be matrices for the synthesis of specific mechanism, through the information (matrix) RNA with the participation of the owner's ribosoma (see,). Plasmid and phage DNA can also be cut by restrictions and shifted with ligases.

Genetic engineering originated when scientists found that with the help of restrictions and ligases can be inserted into or moderate phage alien, and then infect them. Difficulties with insertion in bacterial and phages (they are called versions, carriers) of the highest organisms were quickly overcome. Now genetic engineers are hard looking for moderates who could become safe vectors for.

Already, genetic engineering can give in unlimited quantities and other people needed to treat genetic diseases (for example, insulin, etc.). They are synthesized breeding in large quantities in which the corresponding ones were introduced. In the near future, inhibitors (moderators) of malignant tumors will be obtained, for the treatment of viral diseases, enkephalins and endorphins for the treatment of mental diseases. In principle, you can make the synthesis of meat or milk. At the end of our century, the problem of the directional change of higher plants will be solved, which will revolutionize agriculture. First of all it will be about creating

1. Opportunities for genetic engineering. four

2. History of genetic engineering. 6.

3. Genetic engineering as a science. Methods of genetic engineering. 10

4. Areas of application of genetic engineering. 12

5. Scientific facts of the danger of genetic engineering. eighteen

Conclusion. 22.

References .. 23

Introduction

The topic of genetic engineering has recently been becoming increasingly popular. Most of all attention is paid to negative consequences to which the development of this branch of science can lead to a very low degree, the benefits that genetic engineering can bring.

The most promising area of \u200b\u200bapplication is the production of drugs using genetically engineering technologies. Recently, there was an opportunity to receive useful vaccines based on transgenic plants. No less interest is the production of food products using all the same technologies.

Genetic engineering is the science of the future. At the moment, worldwide millions of hectares of the Earth are seeded by transgenic plants, unique medical drugs are created, new producers of beneficial substances. Over time, genetic engineering will make it possible to achieve new achievements in medicine, agriculture, food industry and animal husbandry.

The purpose of this work is to study the features of the possibility, the history of development and the application of genetic engineering.

1. Possibilities of genetic engineering

An important part of biotechnology is genetic engineering. Born in the early 70s, she achieved great success today. Methods of genetic engineering transform cells of bacteria, yeast and mammals in the "factory" for the large-scale production of any protein. This makes it possible to analyze in detail the structure and function of proteins and use them as medicines. Currently, the intestinal wand (E. coli) has become a supplier of such important hormones as insulin and somatotropin. Previously, insulin was obtained from animal pancreas cells, so it was very high. To obtain 100 g of crystalline insulin, 800-1000 kg of pancreas is required, and one iron cow weighs 200 - 250 grams. It made insulin expensive and hard to reach for a wide range of diabetics. In 1978, researchers from the company "Gentek" first received insulin in a specially designed strain of intestinal sticks. Insulin consists of two polypeptide chains A and in a length of 20 and 30 amino acids. When connecting their disulfide bonds, native two-stranded insulin is formed. It was shown that it does not contain proteins E. coli, endotoxins and other impurities, does not give side effects, as an insulin of animals, and in biological activity is not

is different. Subsequently, in the cells of E. coli, the synthesis of proinsulin was carried out, for which its DNA copy was synthesized on the RNA matrix using reverse transcriptase. After cleaning the resulting epsulin, it was split and received native insulin, while the stages of extraction and hormone isolating were minimized. Of 1000 liters of culture fluid, you can receive up to 200 grams of hormone, which is equivalent to the amount of insulin, isolated from 1600 kg of pancreas of pigs or cows.

Somatotropin is a human growth hormone secreted by the pituitary gland. The disadvantage of this hormone leads to pituitary dwarfs. If you enter somatotropin in doses of 10 mg per kg of weight three times a week, then for the year the child suffering from its lack may be 100 cm. Previously obtained from a pipe material, from one corpse: 4 - 6 mg somatotropin in terms of recalculation End pharmaceutical preparation. Thus, the available amounts of hormone were limited, in addition, the hormone, obtained by this method, was heterogeneous and could contain slowly developing viruses. In 1980, Genentec developed a somatotropin production technology with bacteria, which was deprived of the shortcomings listed. In 1982, human growth hormone was obtained in E. coli culture and animal cells at the Pasteur Institute in France, and since 1984, industrial production of insulin and the USSR began. In the manufacture of interferon, both E. coli, S. cerevisae (yeast) and the culture of fibroblasts or transformed leukocytes are used. Similar methods also receive safe and cheap vaccines.

On technology recombinant DNA, it is based on the production of highly specific DNA probes, with the help of which the expression of genes in tissues, the localization of genes in chromosomes, detect genes with related functions (for example, in humans and chicken). DNA probes are also used in the diagnosis of various diseases.

The technology of recombinant DNA made it possible to the non-traditional approach "Protein-gene", called "reverse genetics". With this approach, the cell is separated from the cell, the gene of this protein is cloned, it is modified by creating a mutant gene encoding the changed shape of the protein. The resulting gene is introduced into the cell. If it is expressed, carrying its cell and its descendants will synthesize the changed protein. Thus, you can correct defective genes and treat hereditary diseases.

If the hybrid DNA is introduced into a fertilized egg, transgenic organisms expressing mutant gene can be obtained and its descendants transmitting it. The genetic transformation of animals allows you to establish the role of individual genes and their protein products both in the regulation of the activity of other genes and at various pathological processes. With the help of genetic engineering, animal lines resistant to viral diseases are created, as well as animal breeds with human useful features. For example, the microinjection of recombinant DNA containing a bull somatotropin gene in the zygota of the rabbit allowed the transgenic animal with the hyperproduction of this hormone. The animals obtained possessed pronounced acromegaly.

The carriers of the material bases of genes serve chromosomes, which include DNA and proteins. But the formation genes are not chemical, but functional. From a functional point of view, DNA consists of a variety of blocks that store a certain amount of information - genes. The basis of the action of the gene is its ability through RNA to determine protein synthesis. In the DNA molecule, the information determining the chemical structure of protein molecules is recorded. The gene is a part of the DNA molecule, which contains information on the primary structure of a single protein (one gene is one protein). Because there are tens of thousands of proteins in organisms, there are tens of thousands of genes. The combination of all cell genes is its genome. All organism cells contain the same set of genes, but each of them is implemented by various parts of the stored information. Therefore, for example, nervous cells and structurally functional and biological features differ from liver cells.

Now, it is even difficult to predict all the possibilities that will be implemented in the next few decades.

2. History of genetic engineering

The history of high medical and biological technologies, genetic research methods, as, however, the most genetic engineering, is directly related to the eternal desire of a person to improve the breeds of domestic animals and cultivated cultivated people. Selecting, certain individuals from groups of animals and plants and crossing them among themselves, a person, without having the right idea of \u200b\u200bthe inner essence of the processes that occurred within living beings, however, many hundreds and thousands of years created improved breeds of animals and varieties of plants that possess defined useful and necessary properties for people.

In the XVIII and XIX centuries, a lot of attempts were made to find out how signs of generation are transmitted to generation. One important discovery was made in 1760 Botanik Kelreteter, who crossed two types of tobacco, transferring to the pollen of one species on the pestles of another species. Plants obtained from hybrid seeds had signs, intermediate between the signs of both parents. Kelreteiver made a logical conclusion from this that parental signs are transmitted both through pollen (seed cells) and through the seeds (egg cells). However, neither to him, nor its contemporaries engaged in the hybridization of plants and animals, could not reveal the nature of the heredity transmission mechanism. This is partly due to the fact that in those days the cytological foundations of this mechanism were not yet known, but mainly the fact that scientists tried to study the inheritance of all signs of plants at the same time.

The scientific approach when studying the inheritance of certain signs and properties was developed by the Austrian Catholic Monk Gregor Mendel, which in the summer of 1865 began his experiments on the hybridization of plants (to the crossing of various varieties of pea) on the territory of his monastery. He opened the main laws of genetics for the first time. Gregor Mendel achieved success, because he studied the inheritance of individual, clearly different from each other (contrasting) signs, counted the number of descendants of each type and carefully led the detailed records of all its experiments on crossing. Acquaintance with the basics of mathematics allowed him to correctly interpret the obtained data and put forward the assumption that each sign is determined by two hereditary factors. A talented monk researcher was later clearly shown that hereditary properties are not mixed, but are transmitted to offspring in the form of certain units. This brilliant conclusion was subsequently fully confirmed when it was possible to see the chromosomes and find out the features of different types of cell division: mitosis (somatic cells - body cells), meiosis (genital, reproducing, germinative) and fertilization.

Mendel reported on the results of his work at the meeting of the Bunnian society of naturalists and published them in the writings of this society. The meaning of the results they received was not understood by its contemporaries, and these studies did not attract attention from breeding scientists and naturalists for almost 35 years.

In 1900, after the details of the division of cells by type of mitosis, Meiosis and the very fertilization, three researchers - de frieze in Holland, Correns in Germany and Chermak in Austria - conducted a number of experiments and independently of each other immediately opened the laws of heredity, Standed previously described. Later, finding the article by Mendel, in which these laws were clearly formulated for 35 years before them, these scientists were unanimously rewarded with a scientist-inoku, calling the two basic law of heredity by his name.

In the first decade of the 20th century, experiments were carried out with the most diverse plants and animals, and numerous observations were made regarding the inheritance of signs in humans, which clearly showed that all these organisms heredity obeys the same basic laws. It was found that the factors described by Mendel, which determine a separate feature, are located in the chromosomes of the cell nucleus. Subsequently, in 1909, these units were named Danish Botany Iohansen genes (from the Greek word "ge-nose" - genus, origin), and American scientist William Seatton noticed the amazing similarity between the behavior of chromosomes during the formation of Games (sex cells), their fertilization and transfer of Mendelian hereditary factors - genes. Based on these ingenious discoveries, the so-called chromosomal theory of heredity was created.

Actually, genetics itself as a science of heredity and variability of living organisms and the methods of managing them, originated at the beginning of the 20th century. The American Genetic Scientist T. Morgan, together with his employees, conducted numerous experiments, allowed to reveal the genetic basis for the definition of sex and explain a number of unusual forms of inheritance, in which the transmission of a sign depends on the floor of the individual (the so-called signs lined with floor). The next major step forward was made in 1927, when Meller found that, irradiating the fruit fluff-fruit and other organisms by X-rays, you can artificially cause them changes in the genes, that is, mutations. This made it possible to obtain many new mutant genes - additional material for studying heredity. Data on the nature of mutations served as one of the keys to understand and the structure of the genes themselves.

In the 20s of our century, Soviet scientists of the school A.S. The first experiments were carried out, which showed how difficult it is a gene. These ideas were used by J. Watson and F. Creek, which was managed in 1953 in England to create a DNA model and decipher the genetic code. The scientific research work is then associated with the targeted creation of new combinations of genetic material, and led to the emergence of genetic engineering itself.

At the same time, in the 40s, an experienced study of relations between genes and enzymes began. For this purpose, another object was widely used - NEUROSPORA mold mushroom, which could be artificially obtained and explore a number of biochemical mutations associated with the loss of a particular enzyme (protein). Within the last last decades, the most common objects of genetic studies were intestinal wand (Escherichia coli) and some bacteriophages affecting this bacterium.

From the very beginning of the 20th century, it was observed with a relaxing interest in studying the inheritance of certain (specific) signs in humans and to the hereditary transfer of desirable and undesirable signs of pets and cultivated plants. Relying on increasingly deep knowledge of genetic patterns, genetic scientists and breeders learned almost by order to bring livestock breeds that are able to survive in hot climate, cows giving a lot of milk with high fat, chickens carrying large eggs with thin shells, corn grades and wheat with high resistance to certain diseases.

In 1972, the first hybrid (recombinant) DNA was obtained in the USA in the laboratory of P. Berg. Exciting ideas in the field of human genetics and genetic research methods began to be widely developed and applied in medicine itself. In the 70s, it began to decipher the human genome. For more than dozen years, there is a project called the "man's genome". Of the 3 billion pairs of nucleotides, located in the form of solid continuous passages, is still read only about 10 million characters. At the same time, new genetic techniques are created, which increase the speed of reading DNA. Director of the Medical and Genetic Center of the Russian Academy of Medical Sciences V.I. Ivanov definitely believes that "the whole genome will be read about 2020."

3. Genetic engineering as a science. Methods of genetic engineering

Genetic engineering - design in vitro functionally active genetic structures (recombinant DNA), or otherwise - the creation of artificial genetic programs (Baev A.A.). By E.S. Peerbian Genetic Engineering is a system of experimental techniques to design artificial genetic structures in the form of so-called recombinant or hybrid DNA molecules.

This is aimed at a predetermined program to design molecular genetic systems outside the body, followed by the introduction of them in a living organism. At the same time, recombinant DNAs become an integral part of the genetic apparatus of the chipping organism and report new unique genetic, biochemical, and then physiological properties.

The purpose of applied genetic engineering is to design such recombinant DNA molecules, which, when introduced into the genetic apparatus, would give the body to organize, useful for a person.

Recombinant DNA technology uses the following methods:

Specific DNA splitting with restricting nucleases, accelerating the release and manipulation with individual genes;

Fast sequencing of all nucleotides with a purified DNA fragment, which allows you to determine the borders of the gene and the amino acid sequence encoded by it;

Designing recombinant DNA;

Hybridization of nucleic acids, allowing to identify specific RNA or DNA sequences with greater accuracy and sensitivity based on their ability to bind complementary sequences of nucleic acids;

DNA cloning: amplification in vitro with a chain polymerase reaction or the introduction of a DNA fragment into a bacterial cell, which, after such a transformation, reproduces this fragment in millions of copies;

Introduction of recombinant DNA in cells or organisms.

4. Areas of application of genetic engineering

Currently, scientific discoveries in the field of human genetics have actually revolutionary importance, since it is about the possibility of creating a "human genome map", or the "pathological anatomy of the human genome". This genetic card will allow you to install the location of genes that are responsible for certain hereditary diseases on the DNA long helix. According to genetic scientists, these unlimited possibilities have formed the basis for the idea of \u200b\u200bapplying in clinical practice, the so-called gene therapy, which is such a direction of treatment of patients, which is associated with the replacement of affected genes with high biological technologies and genetic engineering. The invasion of the human gene and ensuring their livelihoods is possible both at the level of somatic (all sorts of bodies with certain structural and functional differences) of body cells and at the level of genital, reproducing (germinative) and germinal (embryonic) cells.

Genetic engineering as a kind of therapy - the treatment of a certain genetically determined disease is associated with the supply of an appropriate underspection DNA molecule in order to replace it with the help of its gene, the sector of chromosome, which contains a defect in itself, or to embed into the human genetic material by fusion with the so-called somatic Human body cells having a genetic defect. The task of genetic engineering against a person is to provide the appropriate purposeful impact on a certain gene to correct it towards the correct functioning and ensuring a person suffering from a hereditary disease, a normal, unchanged option of the gene. Unlike medication, drug therapy, such therapy, called genetic engineering, can, apparently, provide a patient a long-term, prolonged, highly efficient, bringing great relief and benefit treatment.

However, all modern methods for administering DNA in living organisms are not able to direct and deliver it to a certain population of cells containing the changed and therefore turning the functioning gene. In other words, the so-called directional transfer, the transport of genes in the conditions of the body (in the in vivo model) is currently impossible.

A different methodological approach based on the extraction of a patient a certain population of cells containing the affected gene, and manipulation with genetic material by replacing the defective genes in cells using genetic engineering (in the in vitro model) and returning them to the place in the body, Where they were taken from the patient, currently in the conditions of medical and genetic centers are possible. This method of gene therapy through genetic engineering has already been used in an experimental attempt to cure two patients who suffered from a rare genetically caused disease, the so-called beta-thalassemia, which, like sickle cell anemia, is also caused by the presence in red blood cells incorrectly arranged and therefore the incorrectly functioning protein. The essence of the manipulation was that the so-called stem cells were isolated from the bone marrow, in the chromosomes of which the hemoglobulin section of the DNA section was introduced in the chromosome. After the patients remaining in the bone marrow, the incorrectly functioning stem cells were almost completely destroyed, the stem cells improved with the help of genetic engineering. Unfortunately, these two attempts turned out to be clinically unsuccessful, since patients died. This first case of the use of genetic engineering in the conditions of the hospital hospital was not allowed and was not approved by the relevant control committees, and its participants were strongly convicted of a gross violation of the rules for conducting research in the field of human genetics.

Almost to other consequences can lead the genetic engineering of reproducing (sex) cells, since the administration of DNA into these cells differs from the correction of a genetic defect in somatic (bodily, non-treatable) cells. It is known that the introduction of other genes in the chromosome of genital cells leads to their transmission to the subsequent generations. In principle, it is possible to introduce certain parts of DNA instead of defective sections to the genetic material of each reproducing cell of a certain person, which is affected by a genetically predetermined disease.

Indeed, this was achieved by mice. Thus, from the female ovary, an egg cell was obtained, which was subsequently fertilized in the tube (in vitro), and then in a chromosome fertilized egg, a foreign section of DNA was introduced. The same fertilized egg with a changed genome was implanted (introduced) into the maternal mouse-female mouse. The source of foreign DNA in one experiment was the genetic material of the rabbit, and in the other - a person.

In order to detect in the period of intrauterine fetal development, the likelihood of the child's birth with certain genetic deviations, such as, for example, Down syndrome or Thai-Sax disease, the research and development technique of the so-called amniocente - predial analysis, during which the sample of biological fluid containing The embryonic cells are taken from an amniotic bag at the early stage of the second trimester of pregnancy. In addition, the method of extracting various nucleus cells from the sample of the mother's placental blood was obtained its further development. The womb cells thus obtained can be used only to detect a limited number of genetically determined diseases under which there are pronounced, coarse disorders in the DNA structure and changes determined by biochemical analyzes. Genetic engineering using recombinant DNA with intrauterine study opens up the ability to correctly diagnose various and numerous hereditary diseases.

In this case, techniques are being developed to create so-called gene "probes", using which can be installed, whether there is a normal, unchanged gene in the chromosome, or an abnormal, defective gene is present. In addition to the use of recombinant DNA, genetic engineering, which is at one of the stages of its formation, in the future will allow the so-called "planning" of human genes, with the calculation so that a certain gene carrying a distorted, pathological information and because of interest For doctors genetics, it could be detected on time and fairly quickly by analogy with the method of using another "labeled" gene. This complex medical and biological technique should help when determining the location of any gene in the morning cells, and not only in those, the probability of detection in which various violations are carried out using the amnocentsis technique.

In recent years, new sections of biomedical sciences have emerged in recent years, such as, for example, high DNA technology, embryonic therapy and cell therapy (cyto-therapy), that is, intrauterine diagnosis and treatment of genetically determined disease as at the formation phase and the development of the embryo (embryo) and at the stage of ripening the fetus. The invasion of embryonic material and manipulation with it have a direct impact on the inheritance of genetic changes, since they have the ability to transmit from generation to generation. Moreover, the genetic diagnosis itself begins to grow into genetic prediction, that is, in a definition, the future fate of a person, fixing the main revolutionary changes in the medicine itself, which, as a result, has the opportunity for complex medical and genetic experiments and the methodology has begun long before the appearance of a "clinical picture of the disease" , sometimes even before the very birth of a person, determine which hereditary agers are threatened. Thus, thanks to the efforts of genetic engineering and specialists in the field of genetic engineering, the so-called "prognostic medicine" was originated in the depths of medical and biological sciences, that is, medicine, "making forecasts for the future."

At the same time, various technologies and techniques of genetic engineering make it possible to predict in the intrauterine period of development of the child, before its birth, not only the presence of a certain hereditary disease, but also describe in detail the medical and genetic properties of the growing embryo and fetus.

With the accumulation of new data on the genetic mapping of the human genome and the description (sequencing) of its DNA, and also because the developed modern methods of studying DNA polymorphisms make it possible to make accessible genetic information about certain structural and functional (including pathological) features of the human body, which, apparently, will be shown in the future, but not yet noticeable now, it becomes possible to obtain with the help of medical and genetic diagnostics of all genetic information about the child not only preclinically, that is, before the manifestation of a certain hereditary disease, and prenatal, that is, before his birth But also more often, that is, even before his conception.

In a completely foreseeable future, thanks to the success and progress in the field of medical-genetic diagnostics, it will be possible according to DNA diagnostics, it is enough to judge by this, for example, what will be the growth of a person, his mental abilities, a predisposition to certain diseases (in particular, to oncological or mental), the doomed on the manifestation and development of any hereditary diseases.

Modern medical and biological technologies make it possible to detect various violations in genes that can express themselves and cause certain ailments, not only at the stage of pronounced clinically disease, but even when there are no signs of pathology and the disease itself will declare itself. Examples of this may be striking man over the age of 40, and even 70 years old, Alzheimer's disease and Huntington's disease. However, in these cases it is possible to detect genes that can cause similar diseases in humans, even before the conception of the patient himself. It is also known that diabetes mellitus can be attributed to the number of diseases. The predisposition to this disease and the genetically determined pathology are inherited and can manifest themselves in case of non-compliance with a certain lifestyle in a mature or old age. It is possible with sufficient confidence that if both parents or one of them suffer from diabetes, the probability of inheritance of the "diabetes" gene or a set of such genes is transmitted to children.

In this case, it turns out to be possible to carry out relevant medical and biological research and put the correct diagnosis in the presence of microscopically small amounts of biological material. Sometimes there are several separate cells enough for this, which will be multiplied in the in vitro culture, and the "genetic portrait" of the test person will be obtained, of course, not on all the genes of his genome (they are tens of thousands!), But on those of them For which there are good reasons to suspect the presence of certain defects. The simultaneous development of methods of cellular and genetic engineering will allow the subsequent stages of the knowledge of the genome to open a practical ability to arbitrarily, and, above all for therapeutic purposes, change the sequence and order of genes, their composition and structure.

Medicine is not the only area of \u200b\u200bgenetic engineering. There are genital engineering of plants, genetic engineering of bacteriological cells.

Recently, new opportunities have appeared in obtaining "edible" vaccines based on transgenic plants.

For transgenic plants in the world, great successes are achieved. They are largely related to the fact that the problem of obtaining the body from the cell, the cell groups or the immature embryo in plants is now not a lot of work. Cellular technology, tissue culture and the creation of regenerants are widely used in modern science.

Consider achievements in the field of crop production, which were obtained in the Siberian Institute of Physiology and Biochemistry of Plant SB RAS.

Thus, in recent years, a number of transgenic plants have been obtained by transferring UGT, ACP, ACB, ACCC genes in their gene, and other selected from various vegetable objects.

As a result of the introduction of these genes, transgenic wheat plants, potatoes, tomatoes, cucumber, soybeans, peas, rapeseed, strawberries, aspen and some others appeared.

The introduction of genes was produced either "shelling" tissues from the "gene gun" (the design of which was developed in our institute), or a genetic vector based on agrobacterial plasmid having built-in target genes and the corresponding promoters.

As a result, a number of new transgenic forms are formed. Here is some of them.

Transgenic wheat (2 grades), which has significantly more intensive growth and brute, is presumably more resistant to drought and other adverse environmental factors. Its productivity and inheritance of acquired properties is being studied.

Transgenic potatoes, who have been observed for three years. It consistently gives a harvest by 50--90 percent above control, acquired almost complete resistance to the herbicides of auxino series and, in addition, its tubers are significantly less "black" on cuts by reducing the activity of polyphenoloxydase.

Transgenic tomato (several varieties), characterized by greater bushyty and yield. In the conditions of the greenhouse of its harvest - up to 46 kg from a square meter (two more than the above control).

Transgenic cucumber (several varieties) gives a greater number of fertile flowers and, consequently, fruits with yields up to 21 kg from a square meter against 13.7 in control.

There are transgenic forms and other plants, many of which also have a number of useful economic signs.

Genetic engineering is the science of today's and tomorrow. Already in the world, tens of millions of hectares are seeded in the world, new drugs are created, new producers of beneficial substances are created. Over time, genetic engineering will become an increasingly powerful tool for new achievements in the field of medicine, veterinary medicine, pharmacology, food industry and agriculture.

5. Scientific facts of hazardous genetic engineering

It should be noted that along with progress, which carries the development of genetic engineering, allocate some facts of the danger of genetic engineering, the main of which are presented below.

1. Genetic engineering is radically different from the removal of new varieties and rocks. Artificial addition of alien genes strongly disrupts precisely adjusted genetic control of a normal cell. Manipulating genes is radically different from the combination of maternal and fatherly chromosomes, which occurs with natural crossing.

2. Currently, genetic engineering is technically imperfect, as it is not able to control the process of embedding a new gene. Therefore, it is impossible to foresee the place of embedding and the effects of the added gene. Even if the location of the gene will be possible to install after it is embedded in the genome, the available DNA information is very incomplete in order to predict the results.

3. As a result of artificial addition of an alien gene, hazardous substances may unforesely form. In the worst case, it can be toxic substances, allergens or other substances harmful to health. Information about this kind of possibilities is still very incomplete.

4. There are no completely reliable methods for inspection for harmlessness. More than 10% of serious side effects of new drugs cannot be revealed, despite carefully conducted research on harmlessness. The degree of risk of the fact that the dangerous properties of new products modified by genetic engineering will remain unnoticed, probably significantly more than in the case of drugs.

5. There are currently insufficient insufficient requirements currently insufficient. They are completely compiled in such a way as to simplify the procedure of approval. They allow you to use extremely insensitive methods of harmlessness. Therefore, there is a significant risk that hazardous food food can be checked unnoticed.

6. Created to date with the help of genetic engineering foods do not have any significant value for humanity. These products satisfy mainly the commercial interests.

7. Knowledge of action on the environment modified with the help of genetic engineering organisms introduced there is completely insufficient. It has not yet been proven that the organisms modified by genetic engineering will not have a harmful effect on the environment. Ecologists made assumptions about various potential environmental complications. For example, there are many opportunities for the uncontrolled distribution of potentially dangerous genes used by genetic engineering, including the transfer of genes by bacteria and viruses. Complications caused in the environment is likely to be able to correct, since the released genes cannot be taken back.

8. New and dangerous viruses may occur. It is experimentally shown that viruses embedded in the genome can be connected to the genes of infectious viruses (the so-called recombination). Such new viruses can be more aggressive than the initial. Viruses can also be less specied. For example, plant viruses can become harmful to useful insects, animals, as well as people.

9. Knowledge of the hereditary substance, DNA, very incomplete. It is known about the function of only three percent of DNA. Riskically manipulated by complex systems, knowledge of which is incomplete. Extensive experience in biology, ecology and medicine shows that it can cause serious unpredictable problems and disorders.

10. Genetic engineering will not help solve the taste of hunger in the world. The assertion that genetic engineering can make a significant contribution to the permission of the problem of hunger in the world, is a scientifically unreasonable myth.

Conclusion

Genetic engineering is a method of biotechnology, which is engaged in research on the restructuring of genotypes. The genotype is not just a mechanical amount of genes, but the complex system developed in the process of evolution of organisms. Genetic engineering allows you to transfer genetic information from one body to another by operations in the test tube. The transfer of genes makes it possible to overcome interspecific barriers and transmit separate hereditary signs of some organisms to others.

The restructuring of genotypes, when performing genetic engineering tasks, is high-quality changes in genes not related to the chromosome structure visible in the microscope. Gene changes are primarily due to the transformation of the chemical structure of DNA. Information on the structure of the protein recorded in the form of a sequence of nucleotides is realized as a sequence of amino acids in the synthesized protein molecule. The change in the sequence of nucleotides in chromosomal DNA, the loss of one and the inclusion of other nucleotides varies the composition of the RNA molecule forming on DNA, and this, in turn, causes a new sequence of amino acids during synthesis. As a result, a new protein begins to synthesize in the cell, which leads to the appearance of new properties from the body. The essence of gene genetic engineering is that individual genes or groups of genes are embedded in the body's genotype. As a result of embedding in the genotype of the previously missing gene, it is possible to force the cell to synthesize the proteins that it has not previously synthesized.

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