What factors can cause mutations? Mutagenesis. Mutagenic factors. "Khabarovsk State Academy of Economics and Law"
The mutation always happens suddenly. The body's genetic material changes: something happens inside chromosomes or genes, and these changes are usually visible to the naked eye. In some cases, the consequences are severe, and sometimes it is possible for the organism. The mutation does not arise by itself. The cause is always a mutagenic factor.
What are mutagenic factors?
Changes in genes and chromosomes are studied by the science of genetics. She also gives the scientific definition of mutagens.
Mutagenic factors are chemical or physical agents that cause changes in the genetic material of a cell. The nature of these agents can be different, and their classification is based on this position.
Types of mutagens
Physical, chemical and biological mutagens are isolated depending on their origin. Any mutagenic factor can be attributed to one of these three main groups.
The impact of agents hostile to the cell can be directed directly to the DNA, and then the molecule of the genetic material loses its original structure. Some mutagens interfere with the process of cell division, and as a result, the hereditary material is not distributed correctly. However, there are also substances that cannot be classified as mutagens by themselves. But the impact on such a chemical combination of certain enzymes turns it into a real mutagenic factor. These substances, which have mutagenic "potential", are called promutagens.
Mutagenic factors. Examples of
Mutagens of physical origin include sources of exposure to ultraviolet radiation, abnormally high or low temperatures, and humidity.
For example, ultraviolet radiation waves with a length of more than 260 nm are absorbed by the plant leaf cell and cause the formation of uncharacteristic pyrimidine dimers (compounds in the DNA chain) in it, which, in turn, cause errors in the reading of genetic material. As a result, new cells are obtained with a "wrong" structure.
Many chemicals are classified as mutagens and promutagens. Examples are reactive oxygen species, nitrates and nitrites, some metals, drugs and those substances that did not exist in nature before the appearance of mankind (household chemicals, food additives and preservatives).
For example, a pregnant woman may not be aware of her situation and may take some antibiotics that are dangerous to the fetus. As a result, the child may develop caused by mutations.
The result of the action of such biological agents on the cell is a process called infectious mutagenesis. For example, the bacterium Helicobacter pylori, which lives in the intestines and stomach of a person, can cause inflammation of the mucous membrane. Inflammation changes the normal course of redox processes in damaged cells, which also changes the structure of the genetic material in them. The processes of DNA repair and the course of normal division of the molecule are disrupted. The result is mutations.
A few words about the process of mutagenesis
Mutagenesis is the very process of mutation. By what mechanisms can it occur?
The most powerful mutagenic factors cause the so-called chromosomal instability. As a result, the genetic material is either distributed unevenly in the divided cells, or the structure of the chromosome itself changes. For example, two chromosomes, under the influence of an aggressive agent, exchange their regions.
A mutagenic factor can also alter the sequence of DNA nucleic acids. Interestingly, they are lethal or cause very serious diseases when important nucleotides are affected, but they can occur without pathology if such nucleic acid sequences are not damaged.
How to protect yourself from exposure to mutagens?
Mutagenic factors are not ubiquitous, so it will still be beneficial to take certain preventive measures.
Antioxidants are an important group of compounds that inhibit the effects of carcinogens. They can help and defend against all sorts of hostile chemical agents. Examples of antioxidants are vitamins A, B and E, beta-carotenes, and flavonoids. These substances are found in very large quantities in vegetables and fruits, as well as in green tea.
It is important to try to protect yourself from harmful physical agents such as UV radiation or tobacco smoke. For example, Australia is home to a very large number of fair-skinned people, and there is often sunny weather. The percentage of cases of melanoma in this country, unfortunately, is high.
Antibiotics should be taken with caution, food is attentive, and preservatives should be minimized. Ideally, of course, it would be to adhere to the principles of a healthy diet.
Mutagenic environmental factors are strong. However, it is quite possible to protect yourself from their effects if you are attentive to your health.
Factors causing mutations at the gene level
Under natural conditions, a mutation appears under the influence of factors of the external and internal environment and is denoted by the term "natural (or spontaneous) mutations".
The cause of gene, or so-called point, mutations is the replacement of one nitrogenous base in the DNK molecule. on the other, the loss, insertion, or rearrangement of nitrogenous bases in the molecule of D.N.K. Hence it follows that a mutating gene in humans can develop pathological conditions, the pathogenesis of which is different.
The factors causing mutations at the gene level were influenced by the corresponding environment (gout, some forms of diabetes mellitus). Such diseases are more often manifested with constant exposure to unfavorable or harmful environmental factors.
(violation of the diet, etc.). A gene mutation can lead to a disruption in the synthesis of proteins that perform plastic functions. The probable cause of such diseases is Ehlers-Danlos syndrome.
Diseases are under study, which are based on the lack of mechanisms for restoring the modified molecule of D.N.K.
Gene mutation can lead to the development of immunodeficiency diseases
(aplasia of the thymus gland in combination with agammaglobulinemia). The reason for the abnormal structure of hemoglobin is the replacement of a glutamic acid residue in a molecule with a valine residue.
A number of gene mutations are known that control the synthesis of blood coagulation factors.
Gene mutations can cause disruption of the transport of various compounds across cell membranes. They are associated with dysfunction of membrane mechanisms and defects in some systems.
If a mutation at the gene level occurs under the action of various physical, chemical, biological factors, then this is called mutagenesis.
The basis of the mutation is the primary damage in the DNK molecule.
Under natural conditions, a mutation appears under the influence of factors of the external and internal environment and is denoted by the term "natural (or spontaneous) mutations".
The cause of gene, or so-called point, mutations is the replacement of one nitrogenous base in the DNK molecule. on the other, the loss, insertion, or rearrangement of nitrogenous bases in the molecule of D.N.K. Hence it follows that a mutating gene in humans can develop pathological conditions, the pathogenesis of which is different.
The factors causing mutations at the gene level were influenced by the corresponding environment (gout, some forms of diabetes mellitus). Such diseases are more often manifested with constant exposure to unfavorable or harmful environmental factors (violation of the diet, etc.). A gene mutation can lead to a disruption in the synthesis of proteins that perform plastic functions. The probable cause of such diseases is Ehlers-Danlos syndrome.
Diseases are under study, which are based on the lack of mechanisms for restoring the modified molecule of D.N.K.
A gene mutation can lead to the development of immunodeficiency diseases (aplasia of the thymus gland in combination with agammaglobulinemia). The reason for the abnormal structure of hemoglobin is the replacement of a glutamic acid residue in a molecule with a valine residue.
A number of gene mutations are known that control the synthesis of blood coagulation factors.
Gene mutations can cause disruption of the transport of various compounds across cell membranes. They are associated with dysfunction of membrane mechanisms and with defects in some systems.
If a mutation at the gene level occurs under the action of various physical, chemical, biological factors, then this is called mutagenesis.
The basis of the mutation is the primary damage in the DNK molecule.
Mutagens
Mutagens(from the Greek. gennbsch - I give birth) - chemical and physical factors that cause hereditary changes - mutations. For the first time artificial mutations were obtained in 1925 by GA Nadsen and GS Filippov in yeast by the action of radioactive radiation of radium; in 1927, G. Möller obtained mutations in Drosophila by the action of X-rays. The ability of chemicals to induce mutations (by the action of iodine on Drosophila) was discovered by I.A.Rapoport. In individuals of flies that developed from these larvae, the frequency of mutations was several times higher than in control insects.
Classification
Mutagens can be various factors that cause changes in the structure of genes, the structure and number of chromosomes. By origin, mutagens are classified into endogenous formed during the life of the organism and exogenous- all other factors, including environmental conditions.
By their nature, mutagens are classified into physical, chemical and biological:
1 physical mutagens
Ш ionizing radiation;
Radioactive decay;
W ultraviolet radiation;
W simulated radio emission and electromagnetic fields;
Excessively high or low temperature.
2.Chemical mutagens
III oxidizing and reducing agents (nitrates, nitrites, reactive oxygen species);
III alkylating agents (eg iodoacetamide);
III pesticides (eg herbicides, fungicides);
Some food additives (for example, aromatic hydrocarbons, cyclamates);
Oil refined products;
W organic solvents;
III drugs (for example, cytostatics, mercury drugs, immunosuppressants).
III A number of viruses can be conventionally attributed to chemical mutagens (the mutagenic factor of viruses is their nucleic acids - DNA or RNA)
3 biological mutagens
III specific DNA sequences - transposons;
Some viruses (measles, rubella, flu);
Metabolic products (lipid oxidation products);
III antigens of some microorganisms.
Ministry of Education and Science of the Russian Federation
Federal Agency for Education
GOUVPO
"Khabarovsk State Academy of Economics and Law"
Department of General Economic Disciplines.
Faculty: Auditor
Abstract on the topic:
Mutations. The influence of environmental factors on mutagenesis.
Completed by a student of the group: BUK-82 Vyazkova Ekaterina Andreevna
Checked by the teacher: Arzumanyan Elena Vladimirovna
Khabarovsk 2008
1.
1.Introduction ……………………………………………………………………….… ..2
2. A bit of history …………………………………………………………………………………………………………………………………………………………………………………………………………… .3
3.Factors influencing mutation …………………………………… ......... 4
5. Consequences of mutations …………………………………………………………. nine
6.Conclusion ………. ………………. ………………………………………… ... 10
7.List of literature ………………………………………………… ……… 11
1. Introduction.
Each new generation of plants and animals is very similar to their parents: when two Siamese cats are crossed, only Siamese kittens appear, and not kittens of any other breed. This tendency of living organisms to resemble their parents is called heredity. Although the similarities between parents and offspring are great, they are usually not absolute. Most traits are strongly influenced by the conditions in which the individual grows and develops.
The branch of biology that deals with the phenomena of heredity and the study of the laws governing the similarities and differences between related organisms is called genetics.
The growth of each plant or animal occurs as a result of division and increase in the size of the cells that make up the organism. This cell division, which is an extremely orderly process, is called mitosis.
Examining a dividing cell in a microscope, after appropriate fixation and staining, one can see in its nucleus oblong dark-colored little bodies called chromosomes. Each chromosome contains numerous hereditary factors, each of which is somehow different from all the others. These hereditary units are called genes; each gene controls the inheritance of one or more traits. Although genes are remarkably stable and are passed down to succeeding generations with great precision, changes occur in them from time to time, called mutations. After the gene
mutated into a new form, this new form turns out to be stable and is usually prone to new changes no more than the original gene.
2. A bit of history.
The rock carvings made many millennia ago in Australia, which depict fused twins, can perhaps be considered the very first evidence of human interest in congenital deformities that has come down to us. Time has preserved very little of such ancient evidence, they are rare. In the Babylonian cuneiform, which is at least four thousand years old, only 62 types of congenital malformations of man are listed and described.
It is likely that millennial myths and legends about mermaids, centaurs, sphinxes, harpies, fauns, Cyclops, and two-faced Janus are also caused by man's interest in deformities. Some vices do have a certain resemblance to such monsters, and human fantasy completed their image.
There were not so many reasons for the appearance of freaks, as it seemed in ancient times - copulation with the devil, the intervention of supernatural forces, unfavorable astral influences, etc. And people still use messengers of astral phenomena - horoscopes - to this day.
In Babylon, and in ancient Greece, and in Rome, the birth of freaks was usually interpreted as an unfavorable omen: it was seen as a warning from above, for example, about the impending severe trials. Sometimes, however, in this way the gods informed about the need to make a particular decision. It is known that at the end of the 4th century the birth of a two-headed child was perceived as approval by the gods of the idea of dividing the Roman Empire into western and eastern parts.
In later times, the attitude towards freaks was not the same everywhere. So, the Inquisition in such cases sent severe punishment to both the child and his mother, thereby strictly crossing the wiles of the devil. However, in countries where the Inquisition was not so active or did not exist at all, ugly people
often attributed a special magical power, the ability to divination, divination by the stars, and the like. And here kinship with otherworldly forces played a positive role: it was they who provided their “relative” with these special qualities. It is possible that mercy towards the holy holy fools in Russia was to some extent explained by just such views.
3. Factors influencing the mutation.
Mutations that appear naturally under the influence of the external environment are designated by the term "spontaneous mutations".
Exposure to a variety of environmental factors, including radiation and a number of chemical compounds, leads to an increase in the frequency of mutations. In 1927, an American geneticist, later Nobel Prize winner Heinrich Möller, showed for the first time that exposure to X-rays leads to a significant increase in the frequency of mutations in Drosophila. This work laid the foundation for a new direction in biology - radiation genetics. Thanks to numerous works carried out over the past decades, we now know that when elementary particles (Y-quanta, electrons, protons and neutrons) enter the nucleus, water molecules are ionized, which, in turn, disrupt the chemical structure of DNA. In these places, DNA breaks occur, which leads to the emergence of additional, radiation-induced mutations.
A large amount of information on the effect of radiation on humans was obtained in the study of the consequences of the bombing of Hiroshima and Nagasaki and the Chernobyl accident.
The first large-scale study of the genetic effects of radiation on humans was carried out by American and Japanese researchers in Hiroshima and Nagasaki. This work began in 1946, that is, almost immediately after the surrender of Japan. The explosions of atomic bombs in Hiroshima and Nagasaki led to the simultaneous death of tens of thousands of people and the massive irradiation of survivors. At that time, the effects of radiation were practically unknown, so the US government decided to conduct a comprehensive study of the consequences of the explosions on the population of the two cities. Then, by chance, Lieutenant of the Medical Service James Neal served in the American army, who before the war was actively involved in genetic research on Drosophila. He was entrusted with the scientific leadership of these works, which immediately acquired a pronounced genetic orientation.
The factors causing mutations at the gene level were influenced by the corresponding environment (gout, some forms of diabetes mellitus). Such diseases are more often manifested with constant exposure to unfavorable or harmful environmental factors (violation of the diet, etc.). A gene mutation can lead to a violation of the synthesis of proteins that perform plastic functions. The probable cause of such diseases is Ehlers-Danlos syndrome.
Diseases based on the lack of mechanisms for restoring the altered DNA molecule are under study.
A gene mutation can lead to the development of immunodeficiency diseases (aplasia of the thymus gland in combination with agammaglobulinemia). The reason for the abnormal structure of hemoglobin is the replacement of the glutamic acid residue in the molecule with the Valine residue.
A number of gene mutations are known that control the synthesis of blood coagulation factors.
Gene mutations can cause disruption of the transport of various compounds across cell membranes. They are associated with dysfunction of membrane mechanisms and with defects in some systems.
If a mutation at the gene level occurs under the action of various physical, chemical, biological factors, then this is called mutagenesis.
The basis of the mutation is the primary damage in the DNK molecule.
Mutations (from Lat. Mutatio - change, change), arising naturally or artificially caused by changes in the hereditary properties of the organism as a result of rearrangements and disturbances in its genetic material - chromosomes and genes. Mutations are the basis of hereditary variability in living nature.
Mutations can be caused by the action of external factors of a physical, chemical or biological nature - these are induced mutations or induced mutagenesis.
Newly occurring mutations are called new mutations or de novo mutations. These include, for example, mutations that underlie a number of autosomal dominant diseases such as achondroplasia (10% of cases
belong to the familial forms), Recklinghausen neurofibromatosis, type I (50-70% familial forms), Alzheimer's disease, Huntington's chorea.
Mutations that go from the normal state of a gene (trait) to a pathological state are called direct.
Mutations that go from a pathological state of a gene (trait) to a normal state are called reverse.
Mutations in somatic cells are called somatic. They form pathological cell clones (a set of pathological cells) and, in the case of the simultaneous presence of normal and pathological cells in the body, lead to cellular mosaicism, for example, in Albright's hereditary osteodystrophy, the expressiveness of the disease depends on the number of abnormal cells.
Somatic mutations can be both familial and sporadic (non-familial) forms. They underlie malignant neoplasms and premature aging processes.
Mutations in the germ cells are called germinal. They are less common than somatic mutations, underlie all hereditary and some congenital diseases and are passed down from generation to generation.
Germinal mutations can be familial and sporadic and are inherited as a predisposition to cancer, such as retinoblastoma and Lee-Fromeny syndrome.
4. General patterns of mutagenesis
Mutagenesis is the process of hereditary changes in the body - mutations. The basis of mutagenesis is changes in nucleic acid molecules that store and transmit hereditary information.
Mutations do not appear instantly. Initially, under the influence of mutagens, a pre-mutation state of the cell occurs. Various repair systems seek to eliminate this condition, and then the mutation is not realized. The basis of the repair systems are various enzymes encoded in the genotype of the cell (organism). Thus, mutagenesis is under the genetic control of the cell; it is not a physicochemical, but a biological process.
For example, enzyme repair systems cut out the damaged DNA section if only one strand is damaged (this operation is performed by endonuclease enzymes), then the DNA section complementary to the remaining strand is completed again (this operation is performed by DNA polymerases), then the restored section is stitched to the ends threads remaining after cutting out the damaged area (this operation is performed by ligases).
There are also more subtle mechanisms of repair. For example, when a nitrogenous base is lost in a nucleotide, it is directly inserted (this applies to adenine and guanine); the methyl group can simply be cleaved off; single-strand breaks are sewn together. In some cases, more complex, poorly studied repair systems operate, for example, when both DNA strands are damaged.
However, with a large number of DNA damage, they can become irreversible. This is due to the fact that: firstly, the repair systems may simply not have time to correct the damage, and secondly, the enzymes of the repair systems themselves may be damaged, irreversible DNA damage leads to the appearance of mutations - persistent changes in hereditary information.
Currently, a wide variety of mutagens are known. Let's consider the mechanism of action of some of them.
5. Consequences of mutations.
About one percent of all newborns are born with chromosomal or gene abnormalities. There is no exact data on how many pregnancies are terminated due to these anomalies before the term. The overwhelming majority of children born with anomalies of the hereditary apparatus also have numerous structural defects - deformities. In general, the damage to human health from genetic disorders is hardly much less than from cardiovascular diseases.
Every year around the world, millions of freak children are born, tens and hundreds of thousands of them are viable. Approximately two thousand years ago, Plutarch, in his essay "On Curiosity" wrote: "... So in Rome there are people who do not care about pictures or statues. ... But they only revolve around the square where freaks are exhibited, staring at the legless , crooked hands,
three-eyed, bird-eyed and looking out for whether a mixture of the two has been born somewhere - a monstrous freak ... "
Now scientists of teratology are dealing with these problems. Teratology is a science that studies the causes of origin, mechanisms of formation and manifestation of congenital malformations.
6. Conclusion.
Our common home is in danger. Scientists came to this opinion in the middle of the 20th century, having made sure that technological progress is fraught with destructive power. Perceptible danger threatens nature and its treasury - gene pools, which create an amazing variety of living forms and fuel the further development of our unique world. Pollution of the biosphere not only tests the compensatory capabilities of nature for strength, but also affects human health and can already harm future generations.
4.General regularities of mutagenesis ………………………………………… ..8
5. Consequences of mutations ………………………………………………………… .9
6.Conclusion ………. ………………. ……………………………………… ... 10
7.List of literature ………………………………………………………… 11
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The information that DNA carries is not something absolutely stable. If it were such, then the range of reactions of related microorganisms to external influences would be constant, which means that a sudden change in environmental conditions for microorganisms with a "frozen" genotype would lead to the extinction of the species. The real instability of the genome is caused by mutations, the exchange of genetic information between donor and recipient.
The term "mutation" was proposed by de Vries as the concept of "abrupt change in a hereditary trait" in the study of heredity in plants. Beijerinck later extended this concept to bacteria. Mutation is a change in the primary structure of a DIC, manifested by a hereditarily fixed loss or change in any trait or group of traits. Mutations are classified according to their origin, the nature of changes in the DNA structure, phenotypic consequences for the mutant cell, etc. The factors causing mutations are known as mutagens.
They are usually physical or chemical in nature. By origin, mutations are isolated, induced, that is, artificially caused, and spontaneous ("wild", arise in a population of bacteria without visible interference from the outside).
Spontaneous mutations. Reverse mutations (reversions).
Replication errors, incorrect formation of complementary base pairs, or structural DNA distortions caused by natural mutagens lead to the appearance of spontaneous mutations. Spontaneous mutations can cause favorable and unfavorable genetic changes. The approximate level of spontaneous mutation is one mutation for every 106-107 cells. The number of mutants in the cell population for different traits is different and can vary from 10-4 to 10-11.
For a specific gene, the mutation frequency is on the order of 10-5, and for a certain pair of nucleotides 10-8. For example, if a million bacteria are sown on a medium containing an antibiotic, one colony can be expected to survive as a result of spontaneous mutation.
Despite the fact that the level of mutations in the bacterial population for individual cells seems to be insignificant, it must be remembered that the bacterial population is huge, and they multiply rapidly. Consequently, the rate of mutations from the point of view of the whole population is quite significant. In addition, mutants that appeared spontaneously and resistant to the action of any antibiotic have an advantage in reproduction over the “wild” type of bacteria and quickly form a stable population.
Reverse mutations (reversions) return a spontaneously mutated cell to its original genetic state. They are observed with a frequency of one cell in 107-108 (that is, at least 10 times less often than direct spontaneous mutations).
In modern educational literature, a more formal classification is also used, based on the nature of changes in the structure of individual genes, chromosomes and the genome as a whole. Within the framework of this classification, the following types of mutations are distinguished:
genomic;
chromosomal;
Genomic: - polyploidization (the formation of organisms or cells, the genome of which is represented by more than two (3n, 4n, 6n, etc.) sets of chromosomes) and aneuploidy (heteroploidy) - a change in the number of chromosomes that is not a multiple of the haploid set (see Inge- Vechtomov, 1989). Depending on the origin of chromosome sets, polyploids distinguish between allopolyploids, which have sets of chromosomes obtained by hybridization from different species, and autopolyploids, which have an increase in the number of sets of chromosomes of their own genome, a multiple of n.
With chromosomal mutations, large changes in the structure of individual chromosomes occur. In this case, there is a loss (deletion) or doubling of a part (duplication) of the genetic material of one or several chromosomes, a change in the orientation of chromosome segments in individual chromosomes (inversion), as well as the transfer of a part of the genetic material from one chromosome to another (translocation) (an extreme case - the union of whole chromosomes, the so-called Robertsonian translocation, which is a transitional option from chromosomal to genomic mutation).
At the gene level, changes in the primary structure of genes' DNA under the influence of mutations are less significant than with chromosomal mutations, however, gene mutations are more common. As a result of gene mutations, substitutions, deletions and insertions of one or more nucleotides, translocations, duplications and inversions of various parts of the gene occur. In the case when only one nucleotide changes under the action of a mutation, one speaks of point mutations. Since DNA contains only two types of nitrogenous bases - purines and pyrimidines, all point mutations with base substitutions are divided into two classes: transitions (replacement of purine with purine or pyrimidine with pyrimidine) and transversion (replacement of purine with pyrimidine or vice versa). There are four possible genetic consequences of point mutations: 1) preservation of the meaning of the codon due to the degeneracy of the genetic code (synonymous nucleotide substitution), 2) change in the meaning of the codon, leading to the replacement of amino acids in the corresponding place of the polypeptide chain (missense mutation), 3) formation of a meaningless codon with premature termination (nonsense mutation). There are three meaningless codons in the genetic code: amber - UAG, ocp - UAA and opal - UGA (in accordance with this, the name and mutations that lead to the formation of meaningless triplets - for example, amber mutation), 4) reverse replacement (stop codon with sense codon).
According to their influence on gene expression, mutations are divided into two categories: mutations of the type of base pair substitutions and the type of frame shift (frameshift). The latter are deletions or insertions of nucleotides, the number of which is not a multiple of three, which is associated with the triplet nature of the genetic code.
A primary mutation is sometimes called a direct mutation, and a mutation that restores the original structure of a gene is called a reverse mutation, or reversion. The return to the original phenotype in a mutant organism due to the restoration of the function of the mutant gene often occurs not due to a true reversion, but due to a mutation in another part of the same gene or even another non-allelic gene. In this case, the recurrent mutation is called a suppressor mutation. The genetic mechanisms by which the mutant phenotype is suppressed are very diverse.
Mutagens (from mutation and other Greek γεννάω - I give birth) are chemical and physical factors that cause hereditary changes - mutations. For the first time artificial mutations were obtained in 1925 by GA Nadsen and GS Filippov in yeast by the action of radioactive radiation of radium; in 1927, G. Möller obtained mutations in Drosophila by the action of X-rays. The ability of chemicals to induce mutations (by the action of iodine on Drosophila) was discovered by I.A.Rapoport. In individuals of flies that developed from these larvae, the frequency of mutations was several times higher than in control insects.
Mutagens can be various factors that cause changes in the structure of genes, the structure and number of chromosomes. By origin, mutagens are classified into endogenous, formed during the life of the organism and exogenous - all other factors, including environmental conditions.
By their nature, mutagens are classified into physical, chemical and biological:
Physical mutagens
ionizing radiation;
radioactive decay;
ultraviolet radiation;
simulated radio emission and electromagnetic fields;
excessively high or low temperature.
Chemical mutagens
oxidizing and reducing agents (nitrates, nitrites, reactive oxygen species);
alkylating agents (eg iodoacetamide);
pesticides (eg herbicides, fungicides);
some food additives (for example, aromatic hydrocarbons, cyclamates);
refined petroleum products;
organic solvents;
medications (for example, cytostatics, mercury medications, immunosuppressants).
A number of viruses can be conventionally classified as chemical mutagens (the mutagenic factor of viruses is their nucleic acids - DNA or RNA).
Biological mutagens
specific DNA sequences - transposons;
some viruses (measles, rubella, flu);
metabolic products (lipid oxidation products);
antigens of some microorganisms.
The development of genetics, which discovered methods for obtaining hereditarily altered forms of microorganisms, expanded the possibilities of using microorganisms in agriculture, industrial production, and medicine. The main method is the induced production of mutants by the effects of mutagens (radiation, chemicals) on wild, naturally occurring cultures of microorganisms. This method manages to create mutants that give tens and hundreds of times more valuable products (antibiotics, enzymes, vitamins, amino acids, etc.).
