Russian scientists from the Institute of General Genetics named after. Vavilov, for the first time in Russia, they received donor blood - not from a donor, but from... skin. And even earlier, the rudiment of a human eye was grown from it.
Does this mean that scientists have finally learned to grow “spare parts” for end-of-life organs and tissues that are personally suitable for each person? AiF asked Maria Lagarkova, Doctor of Biological Sciences, head of the laboratory of the Institute of General Genetics named after. Vavilov RAS, which is engaged in the latest research in the field of stem cells.
The magic of the injection
Yulia Borta, AiF: Maria Andreevna, in addition to blood, a semblance of a mini-heart was grown in your laboratory...
Maria Lagarkova: Yes, we are the first in Russia. But similar work was carried out in the USA, England, and Japan.
“Stem cells have already acquired an unreal number of legends - from sensations that they can heal everything, to horror stories about the development of cancer in stars who used them for rejuvenation.
— Stem cell injections by cosmetologists are complete nonsense. Where did they get them from, how did they get them? Why did they inject in the face, but the tumor appeared in a completely different place? I think that rumors about the connection between cosmetic procedures and the formation of tumors have no basis. Stem cells are very different. They are present in our adult bodies. Bone marrow contains blood stem cells. They can turn into any blood cell. Others can make bone, cartilage or fat, but cannot make blood. The brain contains stem cells that can only develop into brain cells. Each type of stem cell sits in its place throughout its life and is responsible for the reproduction of certain tissues. But there are universal stem cells that can turn into absolutely any cell in the body. They are not present in the adult body. They can be isolated from unclaimed embryos for artificial insemination (IVF) and grown in vitro.
— And they can replace damaged cells in the body?
- According to statistics, they are suitable for only one in ten thousand people. Recently, scientists have solved this problem. For this discovery in 2012, the Japanese S. Yamanaka was awarded the Nobel Prize. You can take a piece of skin from any person - less than a square millimeter, hair or blood, isolate the cells, introduce a set of certain genes into them and get that same universal stem cell, and turn it into whatever we want. Personally, you can make neurons, blood, bone, cartilage - anything that is ideally compatible with him. The Japanese created in this way one of the types of retinal cells. The first stage of clinical trials is now beginning in Japan. Many are working on obtaining insulin-producing cells. Once this happens, it is likely that all diabetics will be cured forever. But there are still a lot of difficulties. It is very difficult to create the cells responsible for hematopoiesis. There is also no understanding of how to make all cells transform 100%.
Otherwise, instead of a nerve, for example, a bone may grow.
No longer fantasy
— Cells have learned to recreate. What about whole organs?
- Not yet. Any organ consists of many types of cells, has a three-dimensional structure, shape, and is penetrated by vessels and nerves. Although mini-organs are already being obtained. In our laboratory we have created a semblance of an eye rudiment. The Japanese grew the germ of a tooth. The Dutch are mini-guts. But it will not be long before a heart grown in a test tube will be transplanted into a person.
- Why?
— There are many unresolved issues. For example, how to deliver cells grown in the laboratory to the desired organ so that they take root, form connections with neighboring ones, and grow blood vessels. This has been successful so far only with certain types of cells. Genetic engineering technologies have reached the point that in any diseased cells it is possible to correct the genetic breakdown that caused the disease. All that remains is to learn how to transplant cells grown in the laboratory back to humans.
Each of the discoveries is of utmost importance for science and humanity.
Intelligence gene
American scientists from California discovered a protein called “klotho” and the KL-VS gene, which is responsible for its production. The latter immediately received the name “intelligence gene”, because this protein can increase a person’s IQ by 6 points at once. Moreover, this protein can be synthesized artificially, and it does not matter what age the person is. Consequently, in the future, scientists will learn to use scientific methods to make people smarter, regardless of their natural intellectual data. Of course, with the help of “klotho” it is impossible to make a genius out of an ordinary person. But it may be possible to help people with intellectual development delays, as well as those suffering from Alzheimer's disease, in the future.
Alzheimer's disease
By the way, about Alzheimer's disease. Since its description in 1906, scientists have not been able to reliably find out the nature of this disease, for what reasons it develops in some people and not in others. But recently there has been a significant breakthrough in the study of this problem. Japanese researchers from Osaka University have discovered a gene that develops Alzheimer's disease in experimental mice. As part of the research, the klc1 gene was identified, which promotes the accumulation of beta-amyloid protein in brain tissue, which is the main factor in the development of Alzheimer's disease. The mechanism of this process has been known for a long time, but previously no one could explain its cause. Experiments have shown that when the klc1 gene is blocked, the amount of beta-amyloid protein accumulating in the brain is reduced by 45%. Scientists hope that in the future their research will help in the fight against Alzheimer's disease, a dangerous disease that affects tens of millions of elderly people around the world.
Gene of stupidity
It turns out that there is not only a gene for intelligence, but also a gene for stupidity. In any case, this is what scientists from Emory University in Texas think. They discovered a genetic disorder called RGS14, which, when turned off, significantly improves the intellectual abilities of experimental mice. It turned out that blocking the RGS14 gene makes the CA2 region in the hippocampus, an area of the brain responsible for accumulating new knowledge and storing memories, more active. Laboratory mice without this genetic mutation began to better remember objects and navigate a maze, as well as better adapt to changing environmental conditions. Scientists from Texas hope in the future to develop a drug that would block the RGS14 gene in a living person. This would give people unprecedented intellectual capabilities and cognitive abilities. But it will take more than a decade before this idea is realized.
Obesity gene
It turns out that obesity also has genetic causes. Over the years, scientists have found different genes that contribute to the appearance of excess weight and large amounts of fat in the body. But the “main” of them at the moment is considered to be IRX3. It turned out that this gene affects the percentage of fat relative to total mass. During laboratory studies, it turned out that mice with damaged IRX3 had half the percentage of body fat than others. And this despite the fact that they were fed the same amount of high-calorie food.
Further study of the genetic mutation of IRX3, as well as the mechanisms of its effect on the body, will make it possible to create effective drugs for obesity and diabetes.
Happiness gene
And the most important thing, in our opinion, is the discovery of geneticists from all those mentioned in this review. Discovered by scientists from the London School of Health, 5-HTTLPR is called the “happy gene.” After all, it turns out that it is responsible for the distribution of the hormone serotonin in nerve cells. It is believed that serotonin is one of the most important factors responsible for a person’s mood; it makes us happy or sad, depending on external conditions. Those with low levels of this hormone are prone to frequent bouts of low mood and depression, and are prone to anxiety and pessimism. British scientists have found that the so-called “long” variation of the 5-HTTLPR gene promotes better delivery of serotonin to the brain, which makes a person feel twice as happy as others. These findings are based on a survey and study of the genetic characteristics of several thousand volunteers. At the same time, the best indicators of life satisfaction were found among those people whose both parents also possess the “happiness gene.”
Telegraph - latest news from Ukraine and the world
It became known that scientists from the University of California at San Francisco have found a gene that is responsible for intelligence. And this will make it possible in the future to artificially increase the intelligence of a person at any age. And this is just one of many recent discoveries in genetics, each of which is of utmost importance for science and Humanity.
Intelligence gene
As mentioned above, American scientists from California discovered a protein called “klotho” and the KL-VS gene, which is responsible for its production. The latter immediately received the name “intelligence gene”, because this protein can increase a person’s IQ by 6 points at once.Moreover, this protein can be synthesized artificially, and it does not matter what age the person is. Consequently, in the future, scientists will learn to use scientific methods to make people smarter, regardless of their natural intellectual data.
Of course, with the help of “klotho” it is impossible to make a genius out of an ordinary person. But it may be possible to help people with intellectual development delays, as well as those suffering from Alzheimer's disease, in the future.
Alzheimer's disease
By the way, about Alzheimer's disease. Since its description in 1906, scientists have not been able to reliably find out the nature of this disease, for what reasons it develops in some people and not in others. But recently there has been a significant breakthrough in the study of this problem. Japanese researchers from Osaka University have discovered a gene that develops Alzheimer's disease in experimental mice.As part of the research, the klc1 gene was identified, which promotes the accumulation of beta-amyloid protein in brain tissue, which is the main factor in the development of Alzheimer's disease. The mechanism of this process has been known for a long time, but previously no one could explain its cause.
Experiments have shown that when the klc1 gene is blocked, the amount of beta-amyloid protein accumulating in the brain is reduced by 45%. Scientists hope that in the future their research will help in the fight against Alzheimer's disease, a dangerous disease that affects tens of millions of elderly people around the world.
Gene of stupidity
It turns out that there is not only a gene for intelligence, but also a gene for stupidity. In any case, this is what scientists from Emory University in Texas think. They discovered a genetic disorder called RGS14, which, when turned off, significantly improves the intellectual abilities of experimental mice.It turned out that blocking the RGS14 gene makes the CA2 region in the hippocampus, an area of the brain responsible for accumulating new knowledge and storing memories, more active. without this genetic mutation, they began to better remember objects and navigate the maze, as well as better adapt to changing environmental conditions.
Scientists from Texas hope in the future to develop a drug that would block the RGS14 gene in a living person. This would give people unprecedented intellectual capabilities and cognitive abilities. But it will take more than a decade before this idea is realized.
Obesity gene
It turns out that obesity also has genetic causes. Over the years, scientists have found different genes that contribute to the appearance of excess weight and large amounts of fat in the body. But the “main” of them at the moment is considered to be IRX3.
It turned out that this gene affects the percentage of fat relative to total mass. During laboratory studies, it turned out that mice with damaged IRX3 had half the percentage of body fat than others. And this despite the fact that they were fed the same amount of high-calorie food.
Further study of the genetic mutation of IRX3, as well as the mechanisms of its effect on the body, will make it possible to create effective drugs for obesity and diabetes.
Happiness gene
And the most important thing, in our opinion, is the discovery of geneticists from all those mentioned in this review. Discovered by scientists from the London School of Health, 5-HTTLPR is called the “happy gene.” After all, it turns out that it is responsible for the distribution of the hormone serotonin in nerve cells.It is believed that serotonin is one of the most important factors responsible for a person’s mood; it makes us happy or sad, depending on external conditions. Those with low levels of this hormone are prone to frequent bouts of low mood and depression, and are prone to anxiety and pessimism.
British scientists have found that the so-called “long” variation of the 5-HTTLPR gene promotes better delivery of serotonin to the brain, which makes a person feel twice as happy as others. These findings are based on a survey and study of the genetic characteristics of several thousand volunteers. At the same time, the best indicators of life satisfaction were found among those people whose both parents also possess the “happiness gene.”
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Introduction
Genetics is a science that studies the patterns of heredity and variability.
Initially, genetics studied general patterns of heredity and variability only on the basis of phenotypic data.
Understanding the mechanisms of heredity, that is, the role of genes as elementary carriers of hereditary information, chromosomal theory of heredity, etc. became possible with the application of the methods of cytology, molecular biology and other related disciplines to the problem of heredity.
Today it is known that genes really exist and are specially marked sections of DNA or RNA - a molecule in which all genetic information is encoded.
1. Famous figures in the field of genetics
Some of the famous scientists in the field of genetics were:
Greger Mendel - studied plant hybridization. Mendel showed that some hereditary inclinations do not mix, but are transmitted from parents to descendants in the form of discrete (separate) units. The patterns of inheritance he formulated later became known as Mendel’s laws:
A) Law of uniformity of first generation hybrids.
B) The law of splitting characteristics.
C) The law of independent inheritance of characteristics.
Thomas Morgan.
Thomas Morgan developed the theory of genes as carriers of certain hereditary properties. Based on Morgan's laws, modern science, a century later, builds:
Breeding work with both plant and animal organisms,
Experiments with stem cells,
Transgenic products
Genetic Engineering,
Cloning,
Diagnosis of genetic diseases.
All this is the legacy of the works of the American scientist, and Thomas Morgan also proposed the term - Genetics, to designate a new science.
Nikolai Ivanovich Vavilov.
Russian geneticist, plant breeder, geographer, author of the law of homological series in the hereditary variability of organisms.
The creator of the doctrine of the biological foundations of selection and the centers of origin and diversity of cultivated plants.
Karl Landsteiner is an Austrian physician, chemist, immunologist, and infectious disease specialist.
First researcher in the field:
Immunohematology and immunochemistry,
Described the blood group system.
Unfortunately, it is impossible to list all the scientists, but their names immortalize the syndromes and diseases that they studied.
2. Genetic diseases
Genetic are diseases that arise due to defects in genes, chromosomal abnormalities.
Hereditary are diseases, the occurrence and development of which is associated with defects in the hereditary apparatus of cells, inherited through gametes.
Every healthy person has 6-8 damaged genes, but they do not disrupt cell functions and do not lead to disease, since they are recessive. If a person inherits two similar abnormal genes from his mother and father, he becomes ill. The probability of such a coincidence is extremely low, but it increases sharply if the parents are relatives (i.e. have a similar genotype). For this reason, the incidence of genetic diseases increases in closed population groups.
Each gene in the human body is responsible for the production of a specific protein. Due to the manifestation of a damaged gene, the synthesis of an abnormal protein begins, which leads to impaired cell function and developmental defects.
Down syndrome.
Down syndrome (trisomy on chromosome 21) is one of the forms of genomic pathology, in which most often the karyotype is represented by 47 chromosomes instead of the normal 46, since chromosomes of the 21st pair, instead of the normal two, are represented by three copies. There are two more forms of this syndrome.
The syndrome was named after the English physician John Down, who first described it in 1866.
The word "syndrome" means a set of signs or characteristics. When using this term, the preferred form is “Down syndrome” rather than “Down disease.”
Physical characteristics of children with Down syndrome.
Outwardly, such children are in many ways similar to their parents. However, the extra chromosome leaves its own characteristic imprint.
Signs of children with congenital Down syndrome:
· the child's head is smaller than usual;
· the back of the head is slightly flat;
· the fontanel is larger, overgrows later;
· flattened and wide bridge of the nose;
· palpebral fissures - narrow, obliquely located;
· ears are small, with the upper edge turned out;
· the sky is narrow, vaulted and high.
Other external features of children with Down syndrome are rare. Often these children have heart problems (heart disease - in 40% of cases). Other internal organs are usually normal.
Turner syndrome.
A clear connection between the occurrence of Turner syndrome and age and any diseases of the parents has not been identified. However, pregnancies are usually complicated by toxicosis, the threat of miscarriage, and childbirth is often premature and pathological. Features of pregnancies and childbirth ending in the birth of a child with Turner syndrome are a consequence of chromosomal pathology of the fetus. Impaired formation of the gonads in Turner syndrome is caused by the absence or structural defects of one sex chromosome (X chromosome).
In the embryo, primary germ cells are formed in almost normal numbers, but in the second half of pregnancy they undergo rapid involution (reverse development), and by the time the child is born, the number of follicles in the ovary is sharply reduced compared to the norm or they are completely absent. This leads to severe deficiency of female sex hormones, sexual underdevelopment, and in most patients to primary amenorrhea (absence of menstruation) and infertility. The resulting chromosomal abnormalities are the cause of developmental defects. It is also possible that concomitant autosomal mutations play a role in the appearance of malformations, since there are conditions similar to Turner syndrome, but without visible chromosomal pathology and sexual underdevelopment.
In Turner syndrome, the gonads are usually undifferentiated connective tissue cords that do not contain gonadal elements. Less common are rudiments of the ovaries and elements of the testicles, as well as rudiments of the vas deferens. Other pathological findings are consistent with the clinical presentation. The most important changes in the osteoarticular system are shortening of the metacarpal and metatarsal bones, aplasia (absence) of the phalanges of the fingers, deformation of the wrist joint, osteoporosis of the vertebrae. Radiologically, in Turner syndrome, the sella turcica and the bones of the cranial vault are usually not changed. Deformations of the heart and large vessels (patent ductus ductus, patent interventricular septum, narrowing of the aortic mouth), and renal malformations are noted. Recessive genes for color blindness and other diseases appear.
Cystic fibrosis.
The disease is based on a mutation in the CFTR gene, which is located in the middle of the long arm of chromosome 7.
Cystic fibrosis is inherited in an autosomal recessive manner and is registered in most European countries with a frequency of 1:2000 - 1:2500 newborns. In Russia, the average incidence of the disease is 1:10,000 newborns. If both parents are heterozygous (carriers of a mutated gene), then the risk of having a child with cystic fibrosis is 25%. Carriers of only one defective gene (allele) do not suffer from cystic fibrosis. According to research, the frequency of heterozygous carriage of the pathological gene is 2-5%.
About 1000 mutations of the cystic fibrosis gene have been identified. The consequence of a gene mutation is a disruption of the structure and function of a protein called the cystic fibrosis transmembrane conductance regulator (CFTR). The consequence of this is a thickening of the secretions of the exocrine glands, difficulty in evacuation of the secretion and a change in its physicochemical properties, which, in turn, determines the clinical picture of the disease. Changes in the pancreas, respiratory organs, and gastrointestinal tract are recorded already in the prenatal period and steadily increase with the patient’s age. The secretion of viscous secretion by the exocrine glands leads to difficulty in outflow and stagnation, with subsequent expansion of the excretory ducts of the glands, atrophy of the glandular tissue and the development of progressive fibrosis. The activity of intestinal and pancreatic enzymes is significantly reduced. Along with the formation of sclerosis in organs, there is a dysfunction of fibroblasts. It has been established that fibroblasts from patients with cystic fibrosis produce ciliary factor, or M-factor, which has anticiliary activity - it disrupts the functioning of epithelial cilia.
Pathological changes.
Pathological changes in the lungs are characterized by signs of chronic bronchitis with the development of bronchiectasis and diffuse pneumosclerosis. In the lumen of the bronchi there is a viscous content of a mucopurulent nature.
Atelectasis and areas of emphysema are common findings. In many patients, the course of the pathological process in the lungs is complicated by the layering of bacterial infection (pathogenic Staphylococcus aureus, Haemophilus influenzae and Pseudomonas aeruginosa) and the formation of destruction.
In the pancreas, diffuse fibrosis, thickening of interlobular connective tissue layers, and cystic changes in small and medium ducts are detected. In the liver, focal or diffuse fatty and protein degeneration of liver cells, bile stasis in the interlobular bile ducts, lymphohistiocytic infiltrates in the interlobular layers, fibrous transformation and the development of cirrhosis are noted.
With meconium ileus, atrophy of the mucous layer is expressed, the lumen of the intestinal mucous glands is expanded, filled with eosinophilic masses of secretion, in some places there is swelling of the submucosal layer, and widening of the lymphatic gaps. Cystic fibrosis is often combined with various malformations of the gastrointestinal tract.
Hemophilia.
Hemophilia is a hereditary disease associated with impaired coagulation (blood clotting process); With this disease, hemorrhages occur in the joints, muscles and internal organs, both spontaneously and as a result of injury or surgery. With hemophilia, the risk of death of the patient from hemorrhage in the brain and other vital organs, even with minor trauma, increases sharply. Patients with severe hemophilia are subject to disability due to frequent hemorrhages in the joints (hemarthrosis) and muscle tissue (hematomas).
Hemophilia refers to hemorrhagic diathesis caused by a violation of the plasma component of hemostasis (coagulopathy).
Hemophilia occurs due to a change in one gene on chromosome X. There are three types of hemophilia (A, B, C).
· Hemophilia A (a recessive mutation on the X chromosome) causes a deficiency in the blood of an essential protein - the so-called factor VIII (antihemophilic globulin). This hemophilia is considered classic; it occurs most often, in 80-85% of patients with hemophilia. Severe bleeding during injuries and operations is observed at a factor VIII level of 5-20%.
· Hemophilia B (recessive mutation in the X chromosome) deficiency of plasma factor IX (Christmas). The formation of a secondary coagulation plug is disrupted.
· Hemophilia C (autosomal recessive or dominant (with incomplete penetrance) type of inheritance, that is, it occurs in both men and women), blood factor XI deficiency, is known mainly among Ashkenazi Jews. Currently, hemophilia C is excluded from the classification, since its clinical manifestations differ significantly from A and B.
Tay-Sachs disease.
Classification.
There are three forms of Tay-Sachs disease.
Child form - six months after birth, children experience a progressive deterioration in physical abilities and mental abilities: blindness, deafness, and loss of the ability to swallow are observed. As a result of muscle atrophy, paralysis develops. Death occurs before the age of 3-4 years.
Adolescent form - motor-cognitive problems, dysphagia (impaired swallowing), dysarthria (speech disorders), ataxia (unsteadiness of gait), spasticity (contractures and paralysis) develop. Death occurs before the age of 15-16 years.
The adult form occurs between the ages of 25 and 30 years. It is characterized by symptoms of progressive deterioration of neurological functions: impaired and unsteady gait, swallowing and speech disorders, decreased cognitive skills, spasticity, and the development of schizophrenia in the form of psychosis.
Clinical picture.
Newborns with this hereditary disease develop normally in the first months of life. However, at the age of about six months, regression occurs in mental and physical development. The child loses vision, hearing, and the ability to swallow. Convulsions appear. The muscles atrophy and paralysis occurs. Death occurs before the age of 4 years.
The literature describes a rare form of late manifestation of the disease, when clinical symptoms develop at the age of 20-30 years.
Diagnostics.
Tay-Sachs disease is characterized by the presence of a red spot located on the retina opposite the pupil. This spot can be seen with an ophthalmoscope.
Currently, no treatment has been developed. Medical care is limited to alleviating symptoms, and in the case of late forms of the disease, delaying its development.
Patau syndrome.
A characteristic complication of pregnancy when carrying a fetus with Patau syndrome is polyhydramnios: it occurs in almost 50% of cases of Patau syndrome.
Severe congenital defects are observed in Patau syndrome. Children with Patau syndrome are born with a body weight below normal (2500 g). They exhibit moderate microcephaly, impaired development of various parts of the central nervous system, low sloping forehead, narrowed palpebral fissures, the distance between which is reduced, microphthalmia and coloboma, corneal opacity, sunken bridge of the nose, wide base of the nose, deformed ears, cleft upper lip and palate, polydactyly , flexor position of the hands, short neck. 80% of newborns have heart defects: defects of the interventricular and interatrial septa, transposition of blood vessels, etc. Fibrocystic changes in the pancreas, accessory spleens, and embryonic umbilical hernia are observed. The kidneys are enlarged, have increased lobulation and cysts in the cortex, and malformations of the genital organs are detected. SP is characterized by mental retardation.
Due to severe congenital malformations, most children with Patau syndrome die in the first weeks or months (95% before 1 year).
However, some patients live for several years. Moreover, in developed countries there is a tendency to increase the life expectancy of patients with Patau syndrome up to 5 years (about 15% of children) and even up to 10 years (2 - 3% of children).
The survivors suffer from deep idiocy.
Edwards syndrome.
Manifestations of the syndrome.
Children with trisomy 18 are born with a low weight, on average 2177 g. At the same time, the duration of pregnancy is normal or even exceeds the norm.
The phenotypic manifestations of Edwards syndrome are diverse. Most often, anomalies of the cerebral and facial skull occur; the cerebral skull has a dolichocephalic shape. The lower jaw and mouth opening are small. The palpebral fissures are narrow and short. The ears are deformed and in the vast majority of cases are located low, somewhat elongated in the horizontal plane. The lobe and often the tragus are absent. The external auditory canal is narrowed, sometimes absent. The sternum is short, which is why the intercostal spaces are reduced and the chest is wider and shorter than normal. In 80% of cases, abnormal development of the foot is observed: the heel protrudes sharply, the arch sags (rocker foot), the big toe is thickened and shortened. Among the defects of internal organs, the most common defects of the heart and large vessels are: ventricular septal defect, aplasia of one leaflet of the aortic and pulmonary artery valves. All patients have hypoplasia of the cerebellum and corpus callosum, changes in the structures of the olives, severe mental retardation, decreased muscle tone, turning into increased muscle tone with spasticity.
Albinism.
Albinism in humans manifests itself in the absence of normal pigmentation on the skin, hair, and iris of the eyes. This anomaly is an inherited trait, depending on the presence of a recessive, suppressed gene in a homozygous state.
Albinism in humans is often referred to as hypopigmentation. The disease is considered a very rare disorder and the rate varies in different countries. The name of the disease comes from Latin, which means white. Most parents of children with this genetic disorder do not have signs of albinism and have normal hair and eye color. Parents of children with albinism need to be careful and consult a doctor promptly if bruising or unusual bleeding appears.
Causes of albinism.
Albinism in humans is a hereditary condition that is present from birth. This condition is marked by the absence of melanin, the pigment responsible for skin, hair and eye color. Albinism and its causes are associated with the absence or blockade of the enzyme tyrosinase. At the same time, human albino parents can pass this feature on to their child without getting sick themselves. The enzyme tyrosinase is very important for the production of melanin. Translated from Greek, melanin means black. The more melanin, the darker a person's skin. If there are no problems with the production of tyrosinase, then the cause of albinism is a mutation in the genes. The skin of all healthy people has melanin, but albinos do not. It is true that some healthy people have much more melanin than others.
There are different types of albinism in humans and each is associated to varying degrees with a lack of pigment. This condition can be accompanied by various vision problems, and sometimes cause skin cancer. Albinism is inherited by a child if both parents passed on the defective gene. If one parent has the gene, the disease does not occur, but the body has a mutated gene that is passed on to the next generation. This process was given the name autosomal recessive inheritance. Signs of Albinism Albinism, being an inherited condition, is caused by changes in several or one gene. These genes take responsibility for controlling the production, as well as the concentration of melanin in the iris of the eyes and, of course, the skin. Therefore, people may have various vision problems: farsightedness, nearsightedness, astigmatism (curvature of the eye lens). Patients may experience involuntary, constant movements of the eyeball, which are called nystagmus. Albinos have soft pink skin, through which the capillaries are easily visible, and the hair is thin and very soft, white or yellowish in color. Signs of albinism include problems with eye coordination and tracking and fixating on objects. In patients who are ill, the depth of visual perception may decrease and photophobia may occur. Most people with the disease do not have melanin in their skin, which causes sunburn and inability to tan. If the skin is not protected, skin cancer can develop over time.
Marfan syndrome.
Marfan syndrome is a hereditary systemic connective tissue disease characterized by pathological changes in the nervous system, cardiovascular system, musculoskeletal system and other systems and organs of the human body. Marfan syndrome is inherited in an autosomal dominant manner and occurs in people of all races, in almost the same sex ratio. It has been reliably established that in Marfan syndrome the main defect is directly related to collagen disorders, although the possibility of damage to the elastic fibers of the connective tissue cannot be ruled out.
Marfan syndrome causes.
This syndrome is a fairly rare genetic disease and occurs in approximately 1 person out of 5000. As a result of numerous studies, it has been found that this disease is caused by a mutation of the fibrillin protein gene on the fifteenth chromosome, which subsequently leads to abnormalities in the structure and production of fibrillin. According to statistics, in about 75% of cases, the gene for Marfan syndrome is transmitted from parents with this disease to their children. In the remaining 25% of cases, when not one of the parents is diagnosed with this disease, genetic mutations that can provoke the occurrence of Mafan syndrome arise spontaneously in the sperm or egg at the time of conception. The causes of this mutation have not been fully elucidated to date, however, with a 50% probability it can be said that children born with this mutation will pass this disease on to their children. Marfan syndrome symptoms and signs People with Marfan syndrome are often much taller than their relatives and peers and differ in asthenic physique. When compared with the size of the body, their limbs are disproportionately long, and the span of their arms is often much greater than their height. The fingers and toes are in most cases quite thin and long. People with Marfan syndrome have similar facial features: a small jaw, deep-set eyes, an elongated skull, irregular teeth, and a high Gothic sky. People with Marfan syndrome experience the following systemic diseases of the body: Skeletal In addition to long limbs and excessive growth, Marfan syndrome can cause skeletal problems such as curvature of the spine (scoliosis) and deformation of the anterior chest wall (“chicken breast”, depressed chest) . Also common problems in patients with this syndrome are flat feet and soft joints. From the eyes More than 50% of patients with Marfan syndrome have the so-called “lens luxation”. In addition, such people quite often experience myopia (myopia), increased intraocular pressure (glaucoma), clouding of the lens (cataract) and retinal detachment. From the blood vessels and heart, complications of Marfan syndrome associated with the heart are considered the most serious. Over time, this syndrome can cause wall dissection and enlargement of the root of the aorta, which carries blood from the heart muscle throughout the body. Sudden rupture of the aorta can result in death. Often there are problems with the heart valve (usually the aortic and/or mitral valve), which begins to close insufficiently tightly, causing blood to flow back into the heart. Due to such a leak, arrhythmia (irregular heartbeats), shortness of breath and heart murmurs develop. In addition, leaking valves cause a significant enlargement of the heart, making it difficult to function. Other symptoms that can affect the nervous system, lungs, and skin (especially in adolescents and young children) are usually less severe and less common.
Progeria.
Progeria is a rare genetic disease, first described by Guilford, which manifests itself as premature aging of the body associated with its underdevelopment. Progeria is classified into childhood, called Hutchinson (Hutchinson)-Gilford syndrome, and adult progeria, called Werner syndrome. With this disease, there is severe stunting from childhood, changes in skin structure, cachexia, absence of secondary sexual characteristics and hair, underdevelopment of internal organs and the appearance of an old person. In this case, the patient’s mental state corresponds to his age, the epiphyseal cartilaginous plate closes early, and the body has childlike proportions.
Progeria is an incurable disease and is the cause of serious atherosclerosis, which as a result develops strokes and various heart diseases. And in the end, this genetic pathology leads to death, i.e. it is fatal. As a rule, a child can live, on average, thirteen years, although there are cases with a life expectancy of more than twenty.
Ehlers-Danlos syndrome.
Ehlers-Danlos syndrome is a hereditary heterogeneous disease characterized by skin hyperelasticity, which is associated with a defect in collagen formation. Ehlers-Danlos syndrome has different types of inheritance and desmogenesis imperfecta. This pathology depends on individual mutations and can manifest itself as either a moderate course of the disease or life-threatening. Ehlers-Danlos syndrome is considered the most common connective tissue disease. There are no special treatment methods, only therapy in the form of care that can mitigate the consequences of the pathology.
Ichthyosis is a hereditary disease, so the main cause of this skin disease is a gene mutation that is inherited from generation to generation. The biochemistry of the mutation has not been deciphered to date, but the disease manifests itself as a disorder of protein and fat metabolism. As a result of this pathology, excess cholesterol and amino acids accumulate in the blood, which leads to a specific skin reaction.
Gene mutation is the main cause of ichthyosis.
In patients with a gene mutation leading to the development of ichthyosis, there is a slowdown in metabolic processes, disruption of the body's thermoregulation and an increase in the activity of enzymes involved in the oxidative processes of skin respiration.
In addition, patients with ichthyosis experience a decrease in the activity of the endocrine glands - the thyroid gland, adrenal glands, and gonads. These symptoms may appear immediately or increase gradually as the disease progresses. As a result, the deficiency of cellular immunity increases in patients, the ability to absorb vitamin A decreases, and the activity of the sweat glands is disrupted. This means there is an increased chance of detecting diseases of the sweat glands such as syringoma, eccrine spiradenoma, and hydrocystoma.
The complex of these pathologies leads to the appearance of hyperkeratosis - a disruption of the processes of keratinization of the skin and causes the development of ichthyosis. With this disease, amino acid complexes accumulate between the keratinized skin scales, which tightly connect the scales to each other and make them difficult to exfoliate.
Forms of the disease.
Dermatologists distinguish several forms of ichthyosis, each form of the disease has specific symptoms.
Ordinary or vulgar ichthyosis.
This form of the disease occurs most often. The disease is transmitted to children from parents, its first manifestations can be noticed in the 2nd or 3rd year of a child’s life.
Symptoms of ordinary ichthyosis are dry skin, the formation of grayish or white scales on its surface. When ordinary ichthyosis is severe, the scales become rough, dense and take on the appearance of brown scutes. With this form of the disease, various areas of the skin can be affected.
One of the symptoms of ordinary ichthyosis is dry skin.
With ordinary ichthyosis, the intensity of the work of the sweat glands decreases, and dystrophic changes in the nails and hair are often observed. Ichthyosis vulgaris is often accompanied by atopic dermatitis, seborrheic eczema, and sometimes bronchial asthma. In the summer, in patients with ordinary ichthyosis, the severity of symptoms decreases, but in cold weather, on the contrary, an exacerbation of the disease is observed. Often, with age in patients with simple ichthyosis, the manifestations of the disease become less acute.
Ichthyosis of newborns. heredity genetics down syndrome
This form of the disease appears immediately after the baby is born. In dermatology, two subforms of this disease are distinguished: fetal ichthyosis and erythroderma ichthyosiformis.
Fetal ichthyosis, fortunately, is very rare. The disease begins to develop in the period from 12 to 20 weeks of intrauterine development. A newborn baby's skin is covered with large horny plates, so it looks like a turtle shell.
The mouth opening of a child with ichthyosis may be sharply stretched or narrowed, and lip mobility is limited. With fetal ichthyosis, children are often born much prematurely; such newborns are not always viable.
In children with erythroderma ichthyosiformis, the skin at birth is covered with a thin yellowish film. After the film comes off, the skin of the sick child acquires a reddish tint, which does not go away for a long time, and peeling of large skin plates is observed.
Ichthyosiform erythroderma in the bullous form is accompanied by the formation of blisters on the skin. Sometimes sick children experience eye damage (ectropion, blepharitis), keratosis of the skin of the feet and palms, dystrophic changes in hair and nails, and pathological lesions of the nervous and endocrine systems. This disease usually lasts throughout the patient's life.
Ichthyosis sebaceous.
This form of ichthyosis is characterized by intense secretion of drying skin secretions. The disease manifests itself from the first days of a child’s life. In a sick newborn, you may notice severe peeling of the skin, and the baby's body looks as if it is covered with a crust. This form of ichthyosis is the easiest to cure.
Ichthyosis is lamellar.
This form of the disease is also called lamellar ichthyosis; the disease is congenital. A child is born with skin covered with a film. After the film comes off, large scales in the form of plates form on the body.
In this form of the disease, skin lesions remain with the patient for life. But lamellar ichthyosis has minimal effect on internal organs.
Ichthyosis acquired.
The disease in this form is observed very rarely; it manifests itself after 20 years and, as a rule, occurs against the background of chronic gastrointestinal diseases.
The cause of the development of acquired ichthyosis can be diseases such as systemic lupus erythematosus, hypothyroidism, sarcoidosis, AIDS, pellarga, and various hypovitaminosis. Acquired ichthyosis is often a precursor to diseases such as Kaposi's sarcoma, fungal leukemia, Hodgkin's disease, ovarian and mammary tumors in women. Often the appearance of symptoms of ichthyosis is the first sign of the occurrence of malignant tumors.
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The birth of genetics at the turn of two centuries (1900) was prepared by all the previous developments of biological science. XIX century entered the history of biology thanks to two great discoveries: the cell theory formulated by M. Schleiden and T. Schwann (1838), and the evolutionary doctrine of Charles Darwin (1859). Both discoveries played a decisive role in the development of genetics. The cell theory, which declared the cell to be the basic structural and functional unit of all living beings, aroused increased interest in the study of its structure, which later led to the discovery of chromosomes and a description of the process of cell division. In turn, Charles Darwin's theory concerned the most important properties of living organisms, which later became the subject of the study of genetics - heredity and variability. Both theories at the end of the 19th century. united by the idea of the need for the existence of material carriers of these properties, which should be located in cells.
Until the beginning of the twentieth century. all hypotheses about the mechanisms of heredity were purely speculative. Thus, according to the theory of pangenesis by Charles Darwin (1868), tiny particles are separated from all cells of the body - gemmules, which circulate through the bloodstream and enter the germ cells. After the fusion of germ cells, during the development of a new organism, from each gemmule a cell of the same type from which it originated is formed, possessing all the properties, including those acquired by the parents during life. The roots of Darwin's views regarding the mechanism of transmission of traits from parents to offspring through blood lie in the natural philosophy of ancient Greek philosophers, including the teachings of Hippocrates (5th century BC).
Another speculative hypothesis of heredity was put forward in 1884 by K. Nägeli (German). He suggested that a special substance of heredity takes part in the transmission of hereditary inclinations to offspring - idioplasm, consisting of molecules collected in cells into large thread-like structures - micelles. The micelles are connected into bundles and form a network that permeates all cells. Idioplasma is present in both germ cells and somatic cells. The rest of the cytoplasm does not take part in the transmission of hereditary properties. Not being supported by facts, K. Nägeli's hypothesis, however, anticipated data on the existence and structure of material carriers of heredity.
A. Weisman was the first to point out chromosomes as material carriers of heredity. In his theory, he proceeded from the conclusions of the German cytologist Wilhelm Roux (1883) about the linear arrangement of hereditary factors (chromatin grains) in chromosomes and the longitudinal splitting of chromosomes during division as a possible way of distributing hereditary material. The theory of “germ plasm” by A. Weissman received its final form in 1892. He believed that in organisms there is a special substance of heredity - “germ plasm”. The material substrate of the germplasm is the chromatin structure of the nuclei of germ cells. Germ plasm is immortal, through germ cells it is transmitted to descendants, while the body of the organism - the soma - is mortal. Germplasm consists of discrete particles - biophores, each of which determines a separate property of the cells. Biophores are grouped into determinants - particles that determine the specialization of cells. They, in turn, are combined into structures of a higher order (ides), from which chromosomes are formed (according to the terminology of A. Weisman -).
A. Weisman denied the possibility of inheriting acquired properties. The source of hereditary changes, according to his teaching, are the events that occur during the fertilization process: the loss of some information (reduction) during the maturation of germ cells and the mixing of the determinants of the father and mother, leading to the appearance of new properties. A. Weisman's theory had a huge impact on the development of genetics, determining the further direction of genetic research.
By the beginning of the twentieth century. real prerequisites were created for the development of genetic science. The rediscovery of G. Mendel's laws in 1900 played a decisive role. The Czech amateur researcher, monk of the Brunn Monastery Gregor Mendel formulated the basic laws of heredity back in 1865. This became possible thanks to his development of the first scientific genetic method, which was called “hybridological”. It was based on a system of crossings, which made it possible to reveal patterns of inheritance of traits. Mendel formulated three laws and the rule of “gamete purity,” which will be discussed in detail in the next lecture. No less (and perhaps more) important was the fact that Mendel introduced the concept of hereditary inclinations (prototypes of genes), which serve as the material basis for the development of traits, and expressed a brilliant guess about their pairing as a result of the fusion of “pure” gametes.
Mendel's research and his views on the mechanism of inheritance were several decades ahead of the development of science. Even the speculative hypotheses about the nature of heredity discussed above were formulated later. Chromosomes had not yet been discovered and the process of cell division, which underlies the transmission of hereditary information from parents to offspring, had not been described. In this regard, contemporaries, even those who, like Charles Darwin, were familiar with the works of G. Mendel, failed to appreciate his discovery. For 35 years it was not in demand by biological science.
Justice triumphed in 1900, when a secondary rediscovery of Mendel’s laws followed, simultaneously and independently, by three scientists: G. de Vries (Dutch), K. Correns (German) and E. Cermak (Austrian). By repeating Mendel's experiments, they confirmed the universal nature of the patterns he discovered. Mendel began to be considered the founder of genetics, and the development of this science began in 1900.
In the history of genetics, two periods are usually distinguished: the first is the period of classical, or formal, genetics (1900-1944) and the second is the period of molecular genetics, which continues to the present day. The main feature of the first period is that the nature of the material carriers of heredity remained unknown. The concept of “gene”, an analogue of the Mendelian hereditary factor, introduced by the Danish geneticist V. Johansen, was abstract. Here is a quote from his work of 1909: “The properties of an organism are determined by special, under certain circumstances, separable from each other and therefore to a certain extent independent units or elements in the germ cells, which we call genes. At present it is impossible to form any definite idea about the nature of genes; we can only be content with the fact that such elements really exist. But are they chemical entities? We don’t know anything about this yet.” Despite the lack of knowledge about the physicochemical nature of the gene, it was during this period that the basic laws of genetics were discovered and genetic theories were developed that formed the foundation of this science.
The rediscovery of Mendel's laws in 1900 led to the rapid spread of his teachings and numerous, most often successful, attempts by researchers in different countries on different objects (chickens, butterflies, rodents, etc.) to confirm the universal nature of his laws. During these experiments, new patterns of inheritance were revealed. In 1906, English scientists W. Batson and R. Punnett described the first case of deviation from Mendel's laws, later called gene linkage. In the same year, the English geneticist L. Doncaster, in experiments with a butterfly, discovered the phenomenon of linkage of a trait with sex. At the same time, at the beginning of the twentieth century. The study of persistent hereditary changes in mutations begins (G. de Vries, S. Korzhinsky), and the first works on population genetics appear. In 1908, G. Hardy and V. Weinberg formulated the basic law of population genetics about the constancy of gene frequencies.
But the most important studies of the period of classical genetics were the works of the outstanding American geneticist T. Morgan and his students. T. Morgan is the founder and leader of the world's largest genetic school, from which a whole galaxy of talented geneticists emerged. In his research, Morgan was the first to use the fruit fly Drosophila, which became a favorite genetic object and continues to be so today. The study of the phenomenon of gene linkage, discovered by W. Betson and R. Punnett, allowed Morgan to formulate the basic principles of the chromosomal theory of heredity, which we will examine in detail below. The main thesis of this basic genetic theory was that genes are arranged in a linear order on the chromosome, like beads on a string. However, even in 1937, Morgan wrote that there was no agreement among geneticists about the nature of the gene - whether they were real or an abstraction. But he noted that in any case, the gene is associated with a specific chromosome and can be localized there through pure genetic analysis.
Morgan and his colleagues (T. Paynter, K. Bridges, A. Sturtevant, etc.) carried out a number of other outstanding studies: the principle of genetic mapping was developed, a chromosomal theory of sex determination was created, and the structure of polytene chromosomes was studied.
An important event in the period of classical genetics was the development of work on artificial mutagenesis, the first data on which were obtained in 1925 in the USSR by G.A. Nadson and T.S. Filippov in experiments on irradiation of yeast cells with radium. Of decisive importance for the development of work in this direction were the experiments of the American geneticist G. Meller on the effects of X-rays on Drosophila and his development of methods for quantitatively recording mutations. The work of G. Möller gave rise to a huge number of experimental studies using X-rays on various objects. As a result, their universal mutagenic effect was established. Later it was discovered that other types of radiation, such as UV, as well as high temperature and some chemicals, also have a mutagenic effect. The first chemical mutagens were discovered in the 30s. in the USSR in the experiments of V.V. Sakharova, M.E. Lobashev and S.M. Gershenzon and their employees. A few years later, this direction acquired wide scope, especially thanks to the research of A.I. Rapoport in the USSR and S. Auerbach in England.
Research in the field of experimental mutagenesis has led to rapid progress in understanding the mutation process and to the clarification of a number of issues relating to the fine structure of the gene.
Another important area of genetic research during the period of classical genetics concerned the study of the role of genetic processes in evolution. The seminal works in this area belong to S. Wright, R. Fisher, J. Haldane and S.S. Chetverikov. With their works they confirmed the correctness of the basic principles of Darwinism and contributed to the creation of a new modern synthetic theory of evolution, which is the result of a synthesis of Darwin's theory and population genetics.
Since 1940, the second period in the development of world genetics began, which was called molecular, in accordance with the leading position of this direction of genetic science. The main role in the rapid rise of molecular genetics was played by the close alliance of biologists with scientists from other fields of natural science (physics, mathematics, cybernetics, chemistry), in the wake of which a number of important discoveries were made. During this period, scientists established the chemical nature of the gene, determined the mechanisms of its action and control, and made many more important discoveries that turned genetics into one of the main biological disciplines that determine the progress of modern natural science. The discoveries of molecular genetics did not refute, but only revealed the deep mechanisms of those genetic patterns that were revealed by formal geneticists.
The work of J. Beadle and E. Tetum (USA) established that mutations in the bread mold Neurospora crassa block various stages of cellular metabolism. The authors suggested that genes control the biosynthesis of enzymes. A thesis emerged: “one gene, one enzyme.” In 1944, a study on genetic transformation in bacteria carried out by American scientists (O. Avery, K. McLeod and M. McCarthy) showed that DNA is the carrier of genetic information. This conclusion was later confirmed by studying the phenomenon of transduction (J. Lederberg and M. Zinder, 1952) - the transfer of information from one bacterial cell to another using phage DNA.
The listed studies determined an increased interest in the study of the structure of DNA, which resulted in the creation in 1953 of a model of the DNA molecule by J. Watson (American biologist) and F. Crick (English chemist). It was called a double helix because, according to the model, it is built from two polynucleotide chains twisted into a spiral. DNA is a polymer whose monomers are nucleotides. Each nucleotide consists of a five-carbon sugar deoxyribose, a phosphoric acid residue, and one of four nitrogenous bases (adenine, guanine, cytosine, and thymine). This work played a major role in the further development of genetics and molecular biology.
Based on this model, a semi-conservative mechanism of DNA synthesis was first postulated (F. Crick) and then experimentally proven (M. Meselson and F. Stahl, 1957), in which the DNA molecule is divided into two single chains, each of which serves template for the synthesis of the daughter chain. The synthesis is based on the principle of complementarity, previously defined by E. Chargaff (1945), according to which the nitrogenous bases of two DNA chains are located opposite each other in pairs, with adenine connecting only to thymine (A-T), and guanine to cytosine (G-C). One of the consequences of the creation of the model was the deciphering of the genetic code - the principle of recording genetic information. Many scientific teams in different countries have worked on this problem. Success came to Amer. geneticist M. Nirenberg (Nobel laureate), in whose laboratory the first code word, codon, was deciphered. This word became the triplet YYY, a sequence of three nucleotides with the same nitrogenous base - uracil. In the presence of an mRNA molecule consisting of a chain of such nucleotides, a monotonous protein was synthesized containing sequentially connected residues of the same amino acid - phenylalanine. Further deciphering of the code was a matter of technology: using matrices with different combinations of bases in codons, scientists compiled a code table. All the features of the genetic code were determined: universality, tripletity, degeneracy and non-overlapping. Decoding the genetic code in terms of its significance for the development of science and practice is compared with the discovery of nuclear energy in physics.
After deciphering the genetic code and determining the principle of recording genetic information, scientists began to think about how information is transferred from DNA to protein. Research into this problem ended with a complete description of the mechanism for realizing genetic information, which includes two stages: transcription and translation.
After determining the chemical nature of the gene and the principle of its action, the question arose of how the work of genes is regulated. It was first heard in the studies of French biochemists F. Jacob and J. Monod (1960), who developed a scheme for regulating a group of genes that control the process of lactose fermentation in an E. coli cell. They introduced the concept of a bacterial operon as a complex that unites all genes (both structural and regulatory genes) serving any part of metabolism. Later, the correctness of their scheme was proven experimentally by studying various mutations affecting various structural units of the operon.
Gradually, a scheme for the mechanism of eukaryotic gene regulation was developed. This was facilitated by the establishment of the discontinuous structure of some genes and the description of the splicing mechanism.
Influenced by progress in the study of the structure and function of genes in the early 70s. XX century geneticists came up with the idea of manipulating them, first of all, by transferring them from cell to cell. This is how a new direction of genetic research appeared - genetic engineering.
The basis for the development of this direction was formed by experiments during which methods for obtaining individual genes were developed. In 1969, in the laboratory of J. Beckwith, the lactose operon was isolated from the E. coli chromosome using the phenomenon of transduction. In 1970, a team led by G. Corano carried out the first chemical synthesis of the gene. In 1973, a method was developed for obtaining DNA fragments—gene donors—using restriction enzymes that cut the DNA molecule. And finally, a method for obtaining genes was developed based on the phenomenon of reverse transcription, discovered in 1975 by D. Baltimore and G. Temin. To introduce foreign genes into cells, various vectors—carrier molecules—that carried out the transfer process were constructed on the basis of plasmids, viruses, bacteriophages and transposons (mobile genetic elements). The vector-gene complex was called a recombinant molecule. The first recombinant phage DNA-based molecule was constructed in 1974 (R. Murray and D. Murray). In 1975, methods were developed for cloning cells and phages with inserted genes.
Already in the early 70s. The first results of experiments in the field of genetic engineering were obtained. Thus, a recombinant molecule containing two different antibiotic resistance genes (tetracycline and streptomycin) was introduced into an E. coli cell, after which the cell acquired resistance to both drugs.
The set of vectors and introduced genes gradually expanded and the transfer technology was improved. This made it possible to widely use genetic engineering methods for industrial purposes (biotechnology), primarily in the interests of medicine and agriculture. Bacteria were designed to produce biologically active substances. This made it possible to establish on the required scale the synthesis of such drugs necessary for humans as insulin, somatostatin, interferon, tryptophan, etc. A large number of transgenic plants were created that became the owners of valuable properties (resistance to pests, drought, high protein content, etc.) as a result introduction of foreign genes into their genome.
In the 70s work began on sequencing the genomes of various objects, from bacteriophages to humans.
The international genetic program “Human Genome” deserves special attention, the goal of which is to completely decipher the human genetic code and map its chromosomes. In the future, intensive development of a new field of medical genetics is planned - gene therapy, which should help reduce the risk of manifestation of harmful genes and thereby limit the genetic load to the maximum.
History of the development of genetics in Russia
The formation of genetics in Russia occurred in the second decade of the twentieth century. The founder of the first domestic school of geneticists was Yuri Aleksandrovich Filipchenko. In 1916, he began giving a course of lectures at St. Petersburg University “The Doctrine of Heredity and Evolution,” in which he gave a central place to Mendel’s laws and the research of T. Morgan. He made an authorized translation of Morgan’s book “The Gene Theory”. Scientific interests of Yu.A. Filipchenko lay in the field of heredity and variability of qualitative and quantitative traits. He paid special attention to statistical patterns of variability. Yu.A. Filipchenko wrote a number of excellent books, among them the textbook “Genetics,” from which several generations of biologists studied in our country.
During the same period, two more scientific genetic schools were formed: one at the Institute of Experimental Biology (Moscow) under the leadership of Nikolai Konstantinovich Koltsov, the other under the leadership of Nikolai Ivanovich Vavilov began to be created in Saratov, where he was elected as a university professor, and was finally formed in Leningrad on the basis of the All-Union Institute of Plant Growing (VIR).
N.K. Koltsov headed the large Research Institute of Experimental Biology in Moscow. He was the first to express the idea of the macromolecular organization of carriers of heredity (chromosomes) and their self-duplication as a mechanism for transmitting genetic information. Ideas N.K. Koltsov had a strong influence on famous scientists of that period, not only biologists, but also physicists, whose studies of gene structure led to the development of molecular genetics. From the scientific school of N.K. Koltsov included such prominent geneticists as A.S. Serebrovsky, B.L. Astaurov, N.P. Dubinin, N.V. Timofeev-Resovsky, V.V. Sakharov and others.
Outstanding geneticist and breeder N.I. Vavilov won wide recognition for his work in the study of world agriculture and plant resources. He is the author of the doctrine of the centers of origin and diversity of cultivated plants and the doctrine of immunity, as well as the law of homologous series in hereditary variability. In addition, he created a world collection of agricultural and technical plants, including the famous collection of wheat varieties. N.I. Vavilov enjoyed great authority not only among domestic but also among foreign scientists. Scientists from all over the world came to work at the All-Union Institute of Plant Growing (VIR) that he created in Leningrad. Recognition of the merits of N.I. Vavilov was elected president of the International Genetic Congress, which took place in 1937 in Edinburgh. However, circumstances did not allow N.I. Vavilov to attend this congress.
A serious contribution to the development of theoretical genetics was made by the research of Moscow University professor Alexander Sergeevich Serebrovsky and his young colleagues N.P. Dubinina, B.N. Sidorova, I.I. Agol and others. In 1929, they made the discovery of the phenomenon of stepwise allelism in Drosophila, which became the first step towards abandoning the idea of gene indivisibility, which had become established among geneticists. A central theory of gene structure was formulated, according to which a gene consists of smaller subunits - centers that can mutate independently of each other. These studies served as an impetus for the development of work on the study of the structure and function of the gene, which resulted in the development of the modern concept of the complex internal organization of the gene. Later (in 1966) for a series of works in the field of mutation theory N.P. Dubinin was awarded the Lenin Prize.
By the beginning of the 40s. XX century In the USSR, genetics was in its heyday. In addition to those mentioned above, it should be noted the works of B.L. Astaurov on the regulation of sex in silkworms by genetic methods; cytogenetic studies G.A. Levitsky, works by A.A. Sapegina, K.K. Meister, A.R. Zhebraka, N.V. Tsitsin on genetics and plant breeding; M.F. Ivanov on genetics and animal breeding; V.V. Sakharova, M.E. Lobasheva, S.M. Gershenzona, I.A. Rapoport on chemical mutagenesis; S.G. Levit and S.N. Davidenkov on human genetics and the work of many other talented scientists.
However, the political situation of confrontation with the capitalist world that had developed in the USSR at the beginning of World War II led to persecution of scientists working in the field of genetics, which was declared an idealistic bourgeois science, and its adherents were declared agents of world imperialism. Repression fell on the heads of many famous scientists, including N.I. Vavilova, M.E. Lobasheva, G.D. Karpechenko, S.M. Gershenzon and many, many others. Genetics has been set back several decades. T.D. played a significant role in the collapse of genetic science. Lysenko. Being a simple agronomist, he could not rise to the level of classical genetics with its abstract ideas about the gene and therefore simply denied Mendel's laws, Morgan's chromosome theory of heredity, and the doctrine of mutations. Lysenko covered up his scientific inconsistency with generous promises of a rapid rise in agriculture using the methods he advocated for altering plants under the influence of growing conditions, which earned the support of I.V. personally. Stalin. As a shield, Lysenko used the works of the outstanding breeder I.V. Michurina. Unlike world science, our genetics began to be called Michurin’s. Such an “honor” led to Michurin’s reputation as an adherent of Lysenko’s ideas, which did not leave the scientist even after the collapse of the latter’s activities. In fact, I.V. Michurin was an outstanding practical breeder and fruit grower who never had anything to do with the development of the theoretical foundations of genetic science.
Domestic science was finally cleared of “Lysenkoism” only in the mid-60s. Many of the scientists who suffered from repression came out of the “underground”, those who managed to survive, including N.V. Timofeev-Resovsky, M.E. Lobashov, V.V. Sakharov and others. The traditions they preserved and the great potential inherent in their students contributed to rapid progress, although the lag behind the world level, of course, made itself felt. Nevertheless, a new generation of domestic geneticists was rising, who were to bring this science to its previous level. And again, the ranks of world-famous scientists were replenished with Russian names: A.N. Belozersky, V.A. Engelhardt, S.I. Alikhanyan, R.B. Khesina, A.S. Spirina, S.V. Shestakova, S.G. Inge-Vechtomova, Yu.P. Altukhov and many others.
However, new social upheavals caused by perestroika, which led to the outflow of scientific personnel abroad, again prevented our science from gaining the appropriate status. We can only hope that the younger generation, relying on the foundation laid by previous luminaries, will be able to fulfill this noble mission.