Basic problems of genetics. The main problems of genetics What problems does genetic engineering solve
Genetics (from the Greek genesis - origin), the science of heredity and variability of living organisms and methods of managing them. Genetics can rightly be considered one of the most important areas of biology. For thousands of years, man has used genetic methods to improve domestic animals and cultivated plants without understanding the mechanisms underlying these methods. Judging by a variety of archaeological data, already 6,000 years ago people understood that some physical characteristics could be transmitted from one generation to another. By selecting certain organisms from natural populations and crossing them with each other, man created improved varieties of plants and animal breeds that possessed the properties he needed.
However, only at the beginning of the XX century. scientists began to fully realize the importance of the laws of heredity and its mechanisms. Although the advances in microscopy made it possible to establish that hereditary traits are transmitted from generation to generation through spermatozoa and eggs, it remained unclear how the smallest particles of protoplasm could carry the “ingredients” of the vast array of traits that make up each individual organism.
The first truly scientific step forward in the study of heredity was made by the Austrian monk Gregor Mendel, who in 1866 published an article that laid the foundations of modern genetics. Mendel showed that hereditary inclinations do not mix, but are transmitted from parents to descendants in the form of discrete (isolated) units. These units, presented in pairs in individuals, remain discrete and are passed on to subsequent generations in male and female gametes, each of which contains one unit from each pair. In 1909, the Danish botanist Johansen named these units "gedam", and in 1912 the American geneticist Morgan showed that they are located in the chromosomes.
The term "Genetics" was proposed in 1906 by W. Batson.
Since then, genetics has made great strides in explaining the nature of heredity both at the level of the organism and at the level of the gene. The role of genes in the development of an organism is enormous. Genes characterize all the signs of a future organism, such as eye and skin color, size, weight, and much more. Genes are carriers of hereditary information on the basis of which the organism develops.
Depending on the object of study, plant genetics, animal genetics, microorganism genetics, human genetics, etc. are distinguished, and depending on the methods used in other disciplines, biochemical genetics, molecular genetics, ecological genetics, etc.
Genetics makes a huge contribution to the development of the theory of evolution (evolutionary genetics, population genetics). Ideas and methods of genetics are used in all areas of human activity related to living organisms. They are important for solving problems in medicine, agriculture, and the microbiological industry. The latest advances in genetics are associated with the development of genetic engineering.
In modern society, genetic issues are widely discussed in different audiences and from different points of view, including ethical, obviously, for two reasons.
Firstly, genetics affects the most primary properties of living nature, as if the key positions in life manifestations. Therefore, the progress of medicine and biology, as well as all expectations from it, is often focused on genetics. To a large extent, this focus is justified.
Secondly, in recent decades, genetics has been developing so rapidly that it gives rise to both scientific and quasi-scientific promising forecasts. This is especially true of human genetics, whose progress raises ethical problems more acutely than in other areas of biomedical science.
The need to understand the ethical aspects of the use of new technologies has always arisen.
The difference of the modern period is that the speed of the implementation of an idea or scientific development as a result has increased dramatically.
In human genetics, there is a clear connection between scientific research and ethical issues, as well as the dependence of scientific research on the ethical meaning of their final results. Genetics has stepped so far forward that man is on the threshold of such power that allows him to determine his biological fate. That is why the use of all the potential possibilities of medical genetics is real only with strict observance of ethical standards.
Human genetics, rapidly developing in recent decades, has provided answers to many of the questions people have long been interested in: what determines the sex of a child? Why do children look like their parents? What signs and diseases are inherited and which are not, why people are so different from each other, why are closely related marriages harmful?
Interest in human genetics is due to several reasons. First, it is the natural desire of man to know himself. Secondly, after many infectious diseases were defeated - plague, cholera, smallpox, etc. - the relative share of hereditary diseases increased. Thirdly, after the nature of mutations and their significance in heredity were understood, it became clear that mutations can be caused by environmental factors that had not previously been given due attention. An intensive study of the effects of radiation and chemicals on heredity began. Every year, more and more chemical compounds are used in everyday life, agriculture, food, cosmetic, pharmacological industry and other areas of activity, among which many mutagens are used.
In this regard, the following main problems of genetics can be distinguished.
Hereditary diseases and their causes
Hereditary diseases can be caused by disorders in individual genes, chromosomes or sets of chromosomes. For the first time, a connection between an abnormal set of chromosomes and sharp deviations from normal development was discovered in the case of Down syndrome.
In addition to chromosomal disorders, hereditary diseases can be caused by changes in genetic information directly in the genes.
Effective treatments for hereditary diseases do not yet exist. However, there are methods of treatment that alleviate the condition of patients and improve their well-being. They are based mainly on the compensation of metabolic defects caused by disturbances in the genome.
Medical genetic laboratories. Knowledge of human genetics makes it possible to determine the probability of the birth of children suffering from hereditary diseases in cases where one or both spouses are sick or both parents are healthy, but hereditary diseases were found in their ancestors. In some cases, it is possible to predict the birth of a healthy second child if the first one was sick. Such forecasting is carried out in medical genetic laboratories. The widespread use of genetic counseling will save many families from the misfortune of having sick children.
Are abilities inherited? Scientists believe that every person has a grain of talent. Talent is developed through hard work. Genetically, a person is richer in his capabilities, but does not fully realize them in his life.
Until now, there are still no methods for revealing the true abilities of a person in the process of his childhood and youth upbringing, and therefore often the appropriate conditions for their development are not provided.
Does natural selection work in human society? The history of mankind is a change in the genetic structure of populations of the Homo sapiens species under the influence of biological and social factors. Wars, epidemics changed the gene pool of mankind. Natural selection has not weakened over the past 2,000 years, but has only changed: it has been overlaid with social selection.
Genetic engineering uses the most important discoveries of molecular genetics to develop new research methods, obtain new genetic data, as well as in practical activities, in particular in medicine.
Previously, vaccines were made only from killed or weakened bacteria or viruses capable of inducing immunity in humans through the formation of specific antibody proteins. Such vaccines lead to the development of strong immunity, but they also have disadvantages.
It is safer to vaccinate with pure proteins of the shell of viruses - they cannot multiply, tk. they do not have nucleic acids, but they cause the production of antibodies. They can be obtained by genetic engineering. Such a vaccine against infectious hepatitis (Botkin's disease) has already been created - a dangerous and intractable disease. Work is underway to create pure vaccines against influenza, anthrax and other diseases.
Floor correction. Sex reassignment operations in our country began to be done about 30 years ago strictly for medical reasons.
Organ transplant. Organ transplantation from donors is a very complex operation, followed by an equally difficult period of transplant engraftment. Very often the transplant is rejected and the patient dies. Scientists hope that these problems can be solved with the help of cloning.
Cloning is a genetic engineering method in which offspring are obtained from the somatic cell of an ancestor and therefore have exactly the same genome.
Animal cloning solves many problems in medicine and molecular biology, but at the same time creates many social problems.
Scientists see the prospect of reproducing individual tissues or organs of seriously ill people for subsequent transplantation - in this case, there will be no problems with transplant rejection. Cloning can also be used to obtain new drugs, especially those obtained from tissues and organs of animals or humans.
However, despite the tempting prospects, the ethical side of cloning is a concern.
Deformities. The development of a new living being occurs in accordance with the genetic code recorded in the DNA, which is contained in the nucleus of every cell in the body. Sometimes, under the influence of environmental factors - radioactive, ultraviolet rays, chemicals - a violation of the genetic code occurs, mutations occur, deviations from the norm.
Genetics and criminalistics. In judicial practice, cases of establishing kinship are known, when children were mixed up in the maternity hospital. Sometimes this concerned children who grew up in foreign families for more than one year. To establish kinship, methods of biological examination are used, which is carried out when the child is 1 year old and the blood system stabilizes. A new method has been developed - gene fingerprinting, which allows analysis at the chromosomal level. In this case, the age of the child does not matter, and the relationship is established with a 100% guarantee.
Methods for studying human genetics
The genealogical method consists in the study of pedigrees based on the Mendelian laws of inheritance and helps to establish the nature of the inheritance of a trait (dominant or recessive).
The twin method is to study the differences between identical twins. This method is provided by nature itself. It helps to identify the influence of environmental conditions on the phenotype with the same genotypes.
population method. Population genetics studies the genetic differences between individual groups of people (populations), explores the patterns of geographical distribution of genes.
The cytogenetic method is based on the study of variability and heredity at the level of cells and subcellular structures. A connection has been established for a number of serious diseases with chromosomal abnormalities.
The biochemical method makes it possible to identify many hereditary human diseases associated with metabolic disorders. Anomalies of carbohydrate, amino acid, lipid and other types of metabolism are known.
The role of reproduction in the development of living things
All stages in the life of any living being are important, including for humans. All of them are reduced to the cyclic reproduction of the original living organism. And this process of cyclic reproduction began about 4 billion years ago.
Let's consider its features. It is known from biochemistry that many reactions of organic molecules are reversible. For example, amino acids are synthesized into protein molecules that can be broken down into amino acids. That is, under the influence of any influences, both synthesis reactions and splitting reactions occur. In living nature, any organism goes through cyclic stages of splitting the original organism and reproduction from the separated part of a new copy of the original organism, which then again gives rise to an embryo for reproduction. It is for this reason that interactions in living nature last continuously for billions of years. The property of reproduction from the split parts of the original organism of its copy is determined by the fact that a complex of molecules is transferred to the new organism, which completely controls the process of recreating the copy.
The process began with the self-reproduction of complexes of molecules. And this path is quite well fixed in every living cell. Scientists have long paid attention to the fact that in the process of embryogenesis, the stages of the evolution of life are repeated. But then you should pay attention to the fact that in the very depths of the cell, in its nucleus, there are DNA molecules. This is the best evidence that life on Earth began with the reproduction of complexes of molecules that had the property of first splitting the DNA double helix, and then providing the process of recreating the double helix. This is the process of cyclic reconstruction of a living object with the help of molecules that were transmitted at the moment of splitting and which completely controlled the synthesis of a copy of the original object. So the definition of life would look like this. Life is a type of interaction of matter, the main difference of which from the known types of interactions is the storage, accumulation and copying of objects, which introduce certainty into these interactions and transfer them from random to regular ones, while a cyclic reproduction of a living object occurs.
Any living organism has a genetic set of molecules that completely determines the process of recreating a copy of the original object, that is, if the necessary nutrients are available, with a probability of one, as a result of the interaction of a complex of molecules, a copy of a living organism will be recreated. But the supply of nutrients is not guaranteed, and harmful external influences and disruption of interactions within the cell also occur. Therefore, the total probability of recreating a copy is always slightly less than one.
So, from two organisms or living objects, the organism that has a greater total probability of implementing all the necessary interactions will be copied more efficiently. This is the law of evolution of living nature. In other words, it can also be formulated as follows: the more interactions necessary for copying an object are controlled by the object itself, the greater the probability of its cyclic reproduction.
It is obvious that if the total probability of all interactions increases, then the given object evolves; if it decreases, then it involutes; if it does not change, then the object is in a stable state.
The most important function of life activity is the function of self-production. In other words, life activity is the process of satisfying the need for the reproduction by a person of his living being within the framework of the system in which he is included as an element, i.e. in environmental conditions. Taking as an initial thesis the premise that life activity has the most important need for the reproduction of its subject, as the owner of the human body, it should be noted that reproduction is carried out in two ways: firstly, in the process of consuming matter and energy from the environment, and secondly, in the process of biological reproduction, that is, the birth of offspring. The first type of realization of the need in the “environment-organism” link can be expressed as the reproduction of “living from non-living”. Man exists on earth thanks to the constant consumption of the necessary substances and energy from the environment.
IN AND. Vernadsky in his well-known work "Biosphere" presented the process of life on Earth as a constant circulation of matter and energy, in which, along with other creatures, man must be included. Atoms and molecules of physical substances that make up the Earth's biosphere have been included in and out of its circulation millions of times during the existence of life. The human body is not identical to the substance and energy consumed from the external environment, it is the object of its life activity transformed in a certain way. As a result of the realization of the needs for substances, energy, information, another object of nature arises from one object of nature, which has properties and functions that are not at all inherent in the original object. This manifests a special type of activity inherent in man. Such activity can be defined as a need aimed at material and energy reproduction. The content of the realization of this need is the extraction of means of life from the environment. Extraction in a broad sense, both actual extraction and production.
This type of reproduction is not the only one necessary for the existence of life. V.I.Vernadsky wrote that a living organism, “when dying, living and collapsing, gives it its atoms and continuously takes them from it, but a living substance embraced by life always has a beginning in the living”. The second type of reproduction is also inherent in all living things on Earth. Science has proved with sufficient certainty that the direct origin of living things from inanimate matter at this stage of the Earth's development is impossible.
After the emergence and spread of life on Earth, its emergence at the present time on the basis of inorganic matter alone is no longer possible. All living systems that exist on Earth now arise either on the basis of the living, or through the living. Thus, before a living organism reproduces itself materially and energetically, it must be reproduced biologically, that is, be born by another living organism. The reproduction of the living by the living is, first of all, the transfer by one generation to another of genetic material, which determines in the offspring the phenomenon of a certain morphophysiological structure. It is clear that the genetic material is not transmitted from generation to generation on its own, its transmission is also a function of human life.
Question 1. What is biotechnology?
Biotechnology is the use of organisms, biological systems or biological processes in industrial production. The branches of biotechnology include genetic, chromosomal and cell engineering, cloning of agricultural plants and animals, the use of microorganisms in baking, winemaking, drug production, etc.
Question 2. What problems does genetic engineering solve? What are the challenges associated with research in this area?
Genetic engineering methods allow you to introduce genes of other organisms (for example, humans) into the genotype of some organisms (for example, bacteria). Genetic engineering has made it possible to solve the problems of industrial synthesis by microorganisms of various human hormones, such as insulin and growth hormone. By creating genetically modified plants, she provided varieties that are resistant to cold, diseases and pests. The main difficulty for genetic engineering is the observation and control of the activity of DNA introduced from outside. It is important to know whether transgenic organisms are able to withstand the "load" of foreign genes. There is also a danger of spontaneous transfer (migration) of foreign genes to other organisms, as a result of which they can acquire properties that are undesirable for humans and nature. Last but not least is the ethical problem: do we have the right to remake living organisms for our own good?
Question 3. Why do you think the selection of microorganisms is currently of paramount importance?
There are several reasons for the increased interest in microbial breeding:
- ease of selection (compared to plants and animals), which is due to the high reproduction rate and ease of cultivation of bacteria;
- enormous biochemical potential (a variety of reactions carried out by bacteria - from the synthesis of antibiotics and vitamins to the isolation of rare chemical elements from ores);
- simplicity of genetic engineering manipulations; it is also important that the gene built into the DNA of a bacterium automatically starts working, since (unlike eukaryotic organisms) all genes of prokaryotes are active.
As a result, today there are a huge number of examples of the use of new strains of bacteria in practice: the production of food, human hormones, waste processing, wastewater treatment, etc.
Question 4. Give examples of the industrial production and use of the products of the vital activity of microorganisms.
Since ancient times, lactic acid bacteria have provided the preparation of curdled milk and cheese; bacteria, which are characterized by alcoholic fermentation - the synthesis of ethyl alcohol; Yeast is used in baking and winemaking.
Since 1982, insulin synthesized by Escherichia coli has been produced on an industrial scale. This became possible after the human insulin gene was inserted into the DNA of a bacterium using genetic engineering methods. At present, the synthesis of transgenic growth hormone has been established, which is used to treat dwarfism in children.
Microorganisms are also involved in biotechnological processes for cleaning wastewater, processing waste, removing oil spills in water bodies, and obtaining fuel.
Question 5. What organisms are called trans-genic?
Transgenic (genetically modified) are organisms that contain artificial additions to the genome. An example (in addition to the E. coli mentioned above) can be plants, in whose DNA a fragment of the bacterial chromosome is inserted, which is responsible for the synthesis of a toxin that repels harmful insects. As a result, varieties of corn, rice, and potatoes were obtained that are resistant to pests and do not require the use of pesticides. An interesting example is salmon, whose DNA was supplemented with a gene that activates the production of growth hormone. As a result, salmon grew several times faster, and the weight of the fish turned out to be much larger than the norm.
Question 6. What is the advantage of cloning over traditional breeding methods?
Cloning is aimed at obtaining exact copies of an organism with already known characteristics. It allows you to achieve better results in a shorter time than traditional breeding methods. material from the site
Cloning makes it possible to work with individual cells or small embryos. For example, when breeding cattle, a calf embryo at the stage of undifferentiated cells is divided into fragments and placed in surrogate mothers. As a result, several identical calves with the necessary traits and properties develop.
Plant cloning can also be used if necessary. In this case, selection occurs in cell culture (on artificially cultivated isolated cells). And only then, full-fledged plants are grown from cells that have the necessary properties.
The most famous example of cloning is the transplantation of a somatic cell nucleus into a developing egg. This technology in the future will make it possible to create a genetic twin of any organism (or, more importantly, its tissues and organs).
Didn't find what you were looking for? Use the search
On this page, material on the topics:
- Why do you think the selection of microorganisms acquires
- examples of the use of biotechnology achievements
- advances in biotechnology
- biotech cloning with video
- sochineniya biotexnologiya
The textbook complies with the Federal State Educational Standard for Secondary (Complete) General Education, is recommended by the Ministry of Education and Science of the Russian Federation and is included in the Federal List of Textbooks.
The textbook is addressed to students in grade 10 and is designed to teach the subject 1 or 2 hours per week.
Modern design, multi-level questions and tasks, additional information and the possibility of parallel work with an electronic application contribute to the effective assimilation of educational material.
What is the importance of microorganism selection for industry and agriculture?
Biotechnology - it is the use of organisms, biological systems or biological processes in industrial production. The term "biotechnology" has become widespread since the mid-1970s. XX century, although since time immemorial mankind has used microorganisms in baking and winemaking, in the production of beer and in cheese making. Any production based on a biological process can be considered as biotechnology. Genetic, chromosome and cell engineering, cloning of agricultural plants and animals are various aspects of modern biotechnology.
Biotechnology makes it possible not only to obtain products important for humans, such as antibiotics and growth hormone, ethyl alcohol and kefir, but also to create organisms with predetermined properties much faster than using traditional breeding methods. There are biotechnological processes for wastewater treatment, waste processing, oil spill removal in water bodies, and fuel production. These technologies are based on the characteristics of the vital activity of certain microorganisms.
Emerging modern biotechnologies are changing our society, opening up new opportunities, but at the same time creating certain social and ethical problems.
Genetic Engineering. Convenient objects of biotechnology are microorganisms that have a relatively simply organized genome, a short life cycle, and a wide variety of physiological and biochemical properties.
One of the causes of diabetes is the lack of insulin in the body - a hormone of the pancreas. Injections of insulin isolated from the pancreas of pigs and cattle save millions of lives, but in some patients lead to the development of allergic reactions. The optimal solution would be to use human insulin. By genetic engineering, the human insulin gene was inserted into the DNA of Escherichia coli. The bacterium began to actively synthesize insulin. In 1982, human insulin became the first genetically engineered pharmaceutical.
Rice. 107. Countries growing transgenic plants. Almost the entire area under transgenic crops is occupied by genetically modified varieties of four plants: soybeans (62%), corn (24%), cotton (9%) and rapeseed (4%). Varieties of transgenic potatoes, tomatoes, rice, tobacco, beets and other crops have already been created
Growth hormone is currently obtained in a similar way. The human gene, inserted into the genome of bacteria, provides the synthesis of a hormone, injections of which are used in the treatment of dwarfism and restore the growth of sick children to almost normal levels.
Just as in bacteria, the hereditary material of eukaryotic organisms can also be changed with the help of genetic engineering methods. These genetically modified organisms are called transgenic or genetically modified organisms(GMO).
In nature, there is a bacterium that releases a toxin that kills many harmful insects. The gene responsible for the synthesis of this toxin was isolated from the bacterial genome and integrated into the genome of cultivated plants. To date, pest-resistant varieties of corn, rice, potatoes and other agricultural plants have already been developed. Growing such transgenic plants that do not require the use of pesticides has huge advantages, because, firstly, pesticides kill not only harmful, but also beneficial insects, and secondly, many pesticides accumulate in the environment and have a mutagenic effect on living organisms (Fig. 107).
One of the first successful experiments on the creation of genetically modified animals was carried out on mice, in the genome of which the rat growth hormone gene was inserted. As a result, the transgenic mice grew much faster and ended up being twice the size of normal mice. If this experience was of exclusively theoretical significance, then the experiments in Canada already had a clear practical application. Canadian scientists introduced the gene of another fish into the hereditary material of salmon, which activated the growth hormone gene. This resulted in salmon growing 10 times faster and gaining several times their normal weight.
Cloning. The creation of multiple genetic copies of a single individual through asexual reproduction is called cloning. In a number of organisms, this process can occur naturally, remember vegetative propagation in plants and fragmentation in some animals (). If a piece of a ray accidentally breaks off from a starfish, a new full-fledged organism is formed from it (Fig. 108). In vertebrates, this process does not occur naturally.
The first successful animal cloning experiment was carried out by the researcher Gurdon in the late 60s. 20th century at Oxford University. The scientist transplanted a nucleus taken from an albino frog's intestinal epithelium cell into an unfertilized egg of an ordinary frog, whose nucleus had previously been destroyed. From such an egg, the scientist managed to grow a tadpole, which then turned into a frog, which was an exact copy of an albino frog. Thus, for the first time it was shown that the information contained in the nucleus of any cell is sufficient for the development of a full-fledged organism.
Rice. 108. Regeneration of a starfish from one beam
Further research conducted in Scotland in 1996 led to the successful cloning of Dolly the sheep from the mother's mammary epithelial cell (Fig. 109).
Cloning appears to be a promising method in animal husbandry. For example, when breeding cattle, the following technique is used. At an early stage of development, when the cells of the embryo are not yet specialized, the embryo is divided into several parts. From each fragment placed in a foster (surrogate) mother, a full-fledged calf can develop. In this way, you can create many identical copies of a single animal with valuable qualities.
For special purposes, single cells can also be cloned, creating tissue cultures that, in the right media, can grow indefinitely. Cloned cells serve as a substitute for laboratory animals, as they can be used to study the effects on living organisms of various chemicals, such as drugs.
Plant cloning uses a unique feature of plant cells. In the early 60s. 20th century for the first time, it was shown that plant cells, even after reaching maturity and specialization, under suitable conditions, are able to give rise to a whole plant (Fig. 110). Therefore, modern methods of cell engineering make it possible to carry out plant breeding at the cellular level, i.e., to select not adult plants with certain properties, but cells, from which full-fledged plants are then grown.
Rice. 109. Dolly Sheep Cloning
Ethical aspects of the development of biotechnology. The use of modern biotechnologies raises many serious questions for humanity. Could a gene inserted into transgenic tomato plants migrate and integrate into the genome of, for example, bacteria living in the human intestine when the fruits are eaten? Might a transgenic crop resistant to herbicides, diseases, drought, and other stressors, cross-pollinate with related wild plants, transfer these traits to weeds? Will this not result in "superweeds" that will very quickly populate agricultural land? Will the fry of giant salmon accidentally get into the open sea and will this disturb the balance in the natural population? Is the body of transgenic animals able to withstand the load that arises in connection with the functioning of foreign genes? And does man have the right to remake living organisms for his own good?
These and many other issues related to the creation of genetically modified organisms are widely discussed by experts and the public around the world. Special regulatory bodies and commissions created in all countries claim that, despite existing concerns, no harmful effects of GMOs on nature have been recorded.
Rice. 110. Stages of plant cloning (on the example of carrots)
In 1996, the Council of Europe adopted the Convention on Human Rights in the Use of Genomic Technologies in Medicine. The focus of the document is on the ethics of using such technologies. It is argued that no individual can be discriminated against based on information about the features of his genome.
The introduction of foreign genetic material into human cells can have negative consequences. Uncontrolled insertion of foreign DNA into certain parts of the genome can lead to disruption of the genes. The risk of using gene therapy when working with germ cells is much higher than when using somatic cells. When genetic constructs are introduced into germ cells, an undesirable change in the genome of future generations may occur. Therefore, in the international documents of UNESCO, the Council of Europe, the World Health Organization (WHO) it is emphasized that any change in the human genome can only be carried out on somatic cells.
But perhaps the most serious questions arise in connection with the theoretically possible human cloning. Research in the field of human cloning is now banned in all countries, primarily for ethical reasons. The formation of a person as a person is based not only on heredity. It is determined by the family, social and cultural environment, therefore, with any cloning, it is impossible to recreate a personality, just as it is impossible to reproduce all the conditions of upbringing and education that formed the personality of its prototype (nucleus donor). All major religious denominations of the world condemn any interference in the process of human reproduction, insisting that conception and birth must occur naturally.
Animal cloning experiments have raised a number of serious questions for the scientific community, the solution of which depends on the further development of this field of science. Dolly the sheep was not the only clone obtained by Scottish scientists. There were several dozen clones, and only Dolly survived. In recent years, improvements in cloning techniques have made it possible to increase the percentage of surviving clones, but their mortality rate is still very high. However, there is a problem that is even more serious from a scientific point of view. Despite Dolly's victorious birth, her real biological age, associated health problems, and relatively early death remained unclear. According to scientists, the use of the cell nucleus of an elderly six-year-old donor sheep affected the fate and health of Dolly.
It is necessary to significantly increase the viability of cloned organisms, to find out whether the use of specific methods affects the life expectancy, health and fertility of animals. It is very important to minimize the risk of defective development of the reconstructed egg.
The active introduction of biotechnologies into medicine and human genetics has led to the emergence of a special science - bioethics. Bioethics- the science of ethical attitude to all living things, including humans. Ethics are now coming to the fore. Those moral commandments that mankind has been using for centuries, unfortunately, do not provide for new opportunities brought into life by modern science. Therefore, people need to discuss and adopt new laws that take into account the new realities of life.
Review questions and assignments
1. What is biotechnology?
2. What problems does genetic engineering solve? What are the challenges associated with research in this area?
3. Why do you think the selection of microorganisms is now of paramount importance?
4. Give examples of the industrial production and use of the products of vital activity of microorganisms.
5. What organisms are called transgenic?
6. What is the advantage of cloning over traditional breeding methods?
Think! Execute!
1. What are the prospects for the development of the national economy opens up the use of transgenic animals?
2. Can modern humanity do without biotechnology? Organize an exhibition or make a wall newspaper "Biotechnology: past, present, future."
3. Organize and lead a discussion on the topic "Cloning: pros and cons".
4. Give examples of foods in your diet that have been created using biotechnological processes.
5. Prove that biological water treatment is a biotechnological process.
Work with computer
Refer to the electronic application. Study the material and complete the assignments.
Cellular engineering. In the 70s. of the last century, cell engineering began to actively develop in biotechnology. Cell engineering makes it possible to create cells of a new type based on various manipulations, most often hybridization, i.e., fusion of the original cells or their nuclei. A nucleus belonging to a cell of another organism is placed in one of the cells under study. Conditions are created under which these nuclei fuse, and then mitosis occurs, and two single-nuclear cells are formed, each of which contains mixed genetic material. For the first time, such an experiment was carried out in 1965 by the English scientist G. Harris, who combined human and mouse cells. Subsequently, whole organisms were obtained, which are interspecific hybrids obtained by cell engineering. Such hybrids differ from hybrids obtained sexually in that they contain the cytoplasm of both parents (recall that during normal fertilization, the cytoplasm of the spermatozoon does not penetrate the egg). Cell fusion is used to produce hybrids with useful properties between distant species that do not normally interbreed. It is also possible to obtain cell hybrids of plants that carry cytoplasmic genes (i.e., genes found in mitochondria and plastids), which increase resistance to various harmful influences.
Your future profession
1. What is the subject of study of the science of gerontology? Assess how developed this science is in our country. Are there specialists in this field in your region?
2. What personal qualities do you think people working in genetic counseling should have? Explain your point of view.
3. What do you know about professions related to the material in this chapter? Find the names of several professions on the Internet and prepare a short (no more than 7-10 sentences) message about the profession that impressed you the most. Explain your choice.
4. Using additional sources of information, find out what is the subject of the embryologist's study. Where can one acquire such a skill?
5. What knowledge should specialists involved in selection work have? Explain your point of view.
| <<< Назад
|
Forward >>> |
Genetic engineering - problems and achievements
Topic 4. Problems of fundamental science in ecology and nature management
Modern problems of ecology as a science
Modern problems of earth sciences
Geology
Geography
3.3. soil science
1. Modern problems of biology as a science
Genetic engineering - problems and achievements
Genetic Engineering ( presented by... ). See also Appendix
Work on genetic reconstruction, or genetic engineering, began around the 70s of the 20th century, and the first reports of obtaining modified genetically engineered eukaryotic organisms appeared in the middle. 80s.
One of the main areas of biotechnology is the production and use of transgenic plants, i.e. forms that carry in their genome alien genes built in by genetic engineering methods that work normally in the new genome. The genes of animals, humans, bacteria, and other plants that produce new products are integrated into the plant genome. In the future, this direction will be one of the most promising in terms of a significant improvement in the traits necessary for selection.
Improvement of plants by transgenesis goes in the following directions. Problem solved most successfully herbicide resistance, which is important for controlling weeds that clog fields and reduce the yield of cultivated plants. Herbicide-resistant varieties of cotton, corn, rapeseed, soybean, sugar beet, wheat and other plants have been obtained and used.
It is around this direction of transgenesis that serious discussions about the negative consequences of the transfer of herbicide-resistance genes into cultivated plants have currently unfolded. The possibility of spontaneous transfer of these genes to weeds is discussed, since under certain conditions hybridization can occur between cultivated species and their accompanying wild relatives, and, consequently, gene transfer.
Plant resistance to insect pests is another problem successfully solved thanks to the introduction of transgenic plants. Most of the work on this problem is devoted to the deltaendotoxin protein produced by various strains of the bacterium Bacillus turingensis. This protein is toxic to many insect species and is safe for mammals, including humans. In a genome alien to them, the bacterial genes began to function normally and produce a toxin, which, when insects eat plants, leads to their death.
One of the first commercial products of plant genetic engineering was the famous transgenic tomatoes with an almost unlimited shelf life. They were received in two firms by different methods. In the first case, a gene blocker (antisense construct) for an enzyme that plays a major role in the decomposition of tomato fruits was introduced into tomatoes. In another case, the gene for the synthesis of ethylene, a phytohormone that regulates fruit ripening, was blocked. The fruits of such transgenic plants can be stored indefinitely, up to forced treatment with ethylene, when ripe fruits are needed. (Has the release of these tomatoes and consumption so far not caused any negative effects?)
Very promising are studies aimed at obtaining proteins, antibodies, vaccines and other unique components of animal origin for medicine and veterinary medicine through transgenic plants. In these cases, human or animal genes are inserted into the plant genome, which control the synthesis of protein components necessary for medicine. Thus, the plant turns into a kind of factory for the production of the products we need. In the same plan, work is underway to turn animals into donors of proteins, enzymes, hormones, antibodies, vaccines, etc. necessary for medicine and veterinary medicine. However, work on transgenic animals is associated with great difficulties due to the specifics of the object and is still less effective than by plants.
If we evaluate the latest achievements of biotechnology in the methodological aspect, then we are undoubtedly talking about a serious interference in the evolutionarily established genomes of plants, animals, and even man himself. All transgenesis, i.e. the introduction of foreign genes into the genome and their work in it is a serious genetic reconstruction leading to the emergence of new functions, new products of the genome, which introduce a significant imbalance in the evolutionarily established mechanisms of interaction of both intragenomic and external systems. But a person is forced to look for new approaches to the creation of fundamentally new organisms that meet his needs, as he is threatened by a shortage of food, as there is a threat to his health and environmental well-being. Having exhausted natural resources, a person will have to start creating artificial biological systems that provide him with the necessary components, but do not disturb the ecological balance. All disputes and discussions lie precisely in this plane. They are aggravated by the fact that we do not yet know the consequences of our intervention in the genome, although research in this direction is being carried out intensively.
If it is possible to transfer individual genes of systematically distant species and make them work successfully, then why not transfer larger genetic blocks - parts of chromosomes or whole chromosomes. The field of cytogenetics, where these problems are solved, is called chromosome engineering. Methods and approaches of chromosome engineering have been successfully developed for a relatively long time on plants as the most convenient object for these purposes. The transfer of chromosomes or their parts from one genome to another is an even larger reorganization of genomes. So far, this has been successful only in plants, but attempts, and already successful ones, are being made in animals. In this case, we are not talking about individual products of transferred genes, but about obtaining organisms that combine many features of different species.
One of the most significant problems of modern natural science is the problem of biology and genetics of the development of the organism. The mystery for researchers is the mechanisms that form different types of cells, tissues, organs, i.e. responsible for the differentiation of the systems of the body, functioning as a whole. Many researchers deal with this problem, focusing on the genetic aspects of differentiation. Hypotheses have appeared, interesting factual material has been accumulated. However, it seems that this problem is so complex that it will take many years to solve it. The result of its decision - the management of development processes can be extremely important.
Malignant formations are deviations in the normal process of development due to the loss of control of the systems that control development, primarily genetic ones. If we know the mechanisms of action of these systems, then we will be able to control them and make the necessary correction at those stages that determine the normal type of development. There is every reason to believe that the most significant discoveries await us in this area of biology.
The next promising direction in the development of modern biology is the study complex physiological and genetic functions of the body. For plants, this is photosynthesis, nitrogen fixation, etc., for animals, behavior, stress reactivity, etc. There is no need to explain what photosynthesis means for plants. The cells of green plants, some algae and bacteria are able to synthesize organic compounds due to the energy of light. It is through photosynthesis that the process of self-reproduction of a significant part of biological resources takes place. At present, many laboratories around the world are studying this complex process, dissecting it into separate links, in order to then understand and reproduce this complex system as a whole. The genetics of photosynthesis is being studied especially intensively; about a hundred genes are already known that control individual parts of the process.
Another example of a complex physiological and genetic trait is the behavior of animals. For 50 years, the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences has been conducting an experiment on the domestication of foxes. In the initial population, the animals were differentiated according to the types of behavior: aggressive, cowardly, calm towards humans, with subsequent selection from generation to generation. As a result, after more than 50 generations of selection, a new behavioral population of animals has been created. This experiment reproduced in a compressed form the process of domestication of wild animals, which lasted for millennia. It became clear that the most powerful selection factor in the domestication of wild animals was their behavior towards humans. The work carried out showed that today it is extremely important to model the links of the evolutionary process in order to get closer to the reorganization of complex physiological genetic functions - behavior, stress resistance, etc.
Narrow specialization in biology has now led to some weakening of interlevel studies, and thus to difficulties in comprehending experimental data at the evolutionary-population level. This is a very serious shortcoming, since against the backdrop of a huge amount of factual material, especially the molecular genetic plan, the evolutionary meaning of the phenomena under study is often lost. It is very important to preserve the traditions of complex research, also because, in addition to the main line of development of biology (molecule - cell - organism - population), there are many problems that arise at the interface with other sciences. The interpretation of the data obtained in this way is even more complicated and requires general natural science approaches. Examples of such interscientific integration programs can be the following:
1) assessment of anthropogenic (radiation, chemical, etc.) impacts on living systems in a large time range. Naturally, the efforts of biologists, physicians, physicists, chemists, and others are needed to study this problem;
2) ancient DNA research from archaeological samples several thousand years old in order to study a number of aspects of the evolution and variability of the human genome. Such a program is carried out by geneticists in collaboration with archaeologists and paleontologists;
3) creation of bioinformation technologies to study the structure and functions of the genome. These works, which biologists carry out jointly with mathematicians, are now becoming a priority. Deciphering the genomes of humans, animals and plants is a multi-volume genetic texts, and it is possible to comprehend them, bring them into a state of fragments corresponding to genes, only with the help of computer programs.
4) study of hereditary diseases(today there are already more than 2 thousand of them), the genetic component of a person's predisposition to the most common oncological, cardiovascular and many other diseases. This is also the task of many sciences.
The list of related problems and interdisciplinary, interscientific programs could be continued.
18 November 2009Judging by the recent revival of work in the field of gene therapy, this science seems to be beginning to emerge from the shadows of laboratory experiments into the path of promising prospects.
The current autumn turned out to be especially rich in fateful developments: scientific journals reported several important achievements in the field of gene therapy at once. So, with the help of viral delivery of the gene responsible for the formation of the visual pigment of the retina in an experiment on saimiri (squirrel monkey) monkeys with congenital color perception disorders, it was possible for the first time to restore the ability to distinguish between red and green colors in animals, which gives hope for the possibility of using this method for treatment color blindness in humans. Transplant scientists also did not lag behind their colleagues and, in turn, showed that they had learned to improve the condition of donor lungs by activating the gene encoding the synthesis of anti-inflammatory molecules. Even deadly brain diseases will now have to retreat before the new possibilities of gene therapy. Scientists managed to stop the development of adrenoleukodystrophy in two boys by resorting to a modified HIV to deliver the gene responsible for the synthesis of the missing enzyme.
Adrenoleukodystrophy (melanocutaneous leukodystrophy, Addison-Schilder's disease) is a degenerative disease of the white matter of the brain. The type of inheritance is recessive, linked to the X chromosome. This disease, caused by a defect in an enzyme involved in the metabolism of fatty acids, leads to insufficiency of the function of the adrenal glands - endocrine glands that produce vital hormones.
And finally, the equally serious problem of muscular dystrophy is also reflected in the research. A recent study reported that monkeys with gene-damaged myodystrophy were able to achieve an increase in muscle volume and strength after introducing a healthy copy of the desired gene into their cells. Researchers believe that such a method may soon come to the rescue of patients with degenerative muscle diseases.
Mark Kay, director of the Human Gene Therapy program at the Stanford University School of Medicine, is quite satisfied with the recent successes of his colleagues. According to him, researchers working in the field of gene therapy are more optimistic than ever.
Is optimism justified?
Despite the significant advances in gene therapy, scientists still face many obstacles that will have to be overcome on the way to the clinical application of their developments.
Recent work has provided an invaluable service in strengthening the position and demonstrating the prospects of gene therapy. Now scientists working in this area are full of optimism and, judging by the results, their methods will really work in practice soon. A distinctive feature of genetic research is a lot of unforeseen difficulties, but nevertheless, in a rather short period of time for science of 30 years, significant progress has been achieved.
It is already possible to name a number of diseases for which gene therapy methods can be an ideal, if not the only, solution. The simplest example is disorders such as adrenoleukodystrophy or degenerative changes in the retina, when it is necessary to correct the function of only one gene in a small number of cells.
There are, however, other diseases caused by a violation of a single gene, but more difficult to treat. For example, Duchenne muscular dystrophy requires the correction of only one gene, but for the results of treatment to be successful, the defect must be corrected in almost all muscle cells in the whole body. It is also not easy to cure cancer with the help of gene therapy, in which it is necessary to find many malignant cells, often not localized in a solid tumor, but spread over different organs and tissues, but, probably, in combination with other methods, gene therapy can provide a good therapeutic effect. .
Experts identify four main difficulties that must be overcome on the way to the clinical application of gene therapy methods.
1) First of all, it is necessary to obtain a vector specific for this type of cells (virus, nanoparticles, etc. delivery vehicles) in quantities sufficient to achieve the result and not dangerous for the cells themselves.
2) After the vector with the gene included in its structure reaches the desired cell, it must penetrate inside and reach the nucleus. The solution to this problem turned out to be more difficult than expected. Normally, cells have many barriers that prevent new DNA from interacting with the cell's own DNA, but viruses have evolved mechanisms to bypass these barriers and are therefore considered the best tools for gene delivery.
3) Once introduced into the nucleus, the new gene must remain stable for a certain period of time. It is not uncommon for a cell to block a new gene, rendering it ineffective.
4) And, finally, the most serious problem is a possible immune response: the body can reject the vector or the “foreign” protein encoded in the therapeutic gene.
Another common problem is determining how long the effect of gene therapy should be maintained. In the case of fighting an infection or cancer, the therapeutic effect continues until the infection or cancer cells are completely destroyed. But in the case of genetic disorders, courses of gene therapy in most cases must be repeated throughout life.
but on the other hand
It is human nature to be wary of everything new. In the case of gene therapy, it is also impossible to predict with certainty what pitfalls this method may pose. For example, a growing body of evidence suggests that patients may develop very specific problems. In 1998, a widely publicized experiment resulted in the cure of ten children with X-linked severe combined immunodeficiency (SCID) using gene therapy. Later, however, two of them developed leukemia. Each case of the inclusion of new DNA into the cell is accompanied by an increased risk of developing malignant neoplasms. As we delve into the understudied field of gene therapy, it is important not to lose sight of delayed side effects.
Limits of what is permitted
Serious ethical discussions are likely to emerge in the future when it comes time to decide for what purposes gene therapy should be used. There is no doubt that gene therapy should be used to combat severe mental disorders or genetic diseases, but the idea of using such methods to treat behavioral disorders, whether it be depression or drug addiction, raises legitimate doubts. Is it possible to use gene therapy during in vitro fertilization so that the child is born not with the intended fate, but with certain traits of character, high intelligence or athletic abilities determined by the parents? Even if something like this seems like science fiction now, with the development of gene therapy, such questions are sure to arise.
Horizons and perspectives
While the introduction of functional genes into the body remains the main direction of research in the field of gene therapy, one of the promising ways may be the development of active molecules capable of “turning off” defective genes. For example, in the case of Huntington's disease, gene therapy can turn off defective genes that code for the synthesis of abnormal proteins.
An important aspect of all such diseases is treatment at an early stage, before the pathological process spreads to healthy tissues. Preventing a disease is much more effective than dealing with the irreparable consequences inflicted on the body as a result of the development of neurodegenerative diseases or muscular dystrophy.
backRead also:
10 April 2009The first Russian gene therapy drug for cancer is being prepared for clinical trials
Scientists have used a "killer gene" that is introduced into a cancer cell and turns the common antiviral drug ganciclovir into a poison that is deadly to that cell. Ganciclovir, on the other hand, can be administered into the body in tablets or as an injection. The main thing is that a gene is similar to a virus: it is able to infect neighboring tumor cells without touching ordinary ones.
read March 26, 2009A deadly virus created by genetic engineers breaks out of a test tube...
There are many similar scary, but realistic scenarios. It is clear that they need some kind of protection. But how to defend yourself? After all, genetic engineering is good, and no one is going to refuse it. Protection in gene manipulation work is well established, especially where really dangerous viruses are used. But as time goes on, new threats appear ...
read November 17, 2009Chicken eggs with human protein
It is possible to obtain human proteins in chicken eggs without creating genetically modified chickens: it is enough to infect eggs with a harmless virus with an embedded gene for the desired protein.
read October 06, 2009DNA synthesis put on the conveyor
Potential buyers of serial synthetic DNA are industrial chemical and pharmaceutical companies, as well as academic institutions. This promises a gradual transition to industrial rails not just biotechnologies, but their youngest part - synthetic biology.
read September 30, 2009And now - immortality after 30 years ...
Nano- and biotechnologies seem to be completely opposite, but they lead us to the same result - to a fundamental change in man. The development of bioengineering could easily lead us to immortality...
read August 25, 2009Genetic engineering and eugenics - our happy future?
Almost all societies at one time engaged in what we call "eugenics" or "genetic engineering." Why, in the name of what to control human genetics? This is the problem that will be acute for us fifty years from now.