Genetics is a science that studies the patterns of transmission of traits from parent to offspring. This discipline also considers their properties and ability to change. At the same time, special structures - genes - act as carriers of information. At present, science has accumulated enough information. It has several sections, each of which has its own tasks and objects of research. The most important of the sections: classical, molecular, medical genetics and genetic engineering.
Classical genetics
Classical genetics is the science of heredity. This is the property of all organisms to transmit their external and internal signs to offspring during reproduction. Classical genetics also deals with the study of variation. It is expressed in the instability of signs. These changes accumulate from generation to generation. It is only through this variability that organisms can adapt to changes in their environment.
The hereditary information of organisms is contained in genes. Currently, they are considered from the point of view of molecular genetics. Although there were theseconcepts long before this section appeared.
The terms "mutation", "DNA", "chromosomes", "variability" have become known in the process of numerous studies. Now the results of centuries of experiments seem obvious, but once it all started with random crosses. People sought to obtain cows with greater milk yields, larger pigs and sheep with thick wool. These were the first, not even scientific, experiments. However, it was these prerequisites that led to the emergence of such a science as classical genetics. Up until the 20th century, crossbreeding was the only known and available research method. It is the results of classical genetics that have become a significant achievement of the modern science of biology.
Molecular genetics
This is a section that studies all the patterns that are subject to processes at the molecular level. The most important property of all living organisms is heredity, that is, they are able from generation to generation to preserve the main structural features of their body, as well as the patterns of metabolic processes and responses to various environmental factors. This is due to the fact that at the molecular level, special substances record and store all the information received, and then pass it on to the next generations during the process of fertilization. The discovery of these substances and their subsequent study became possible thanks to the study of the structure of the cell at the chemical level. This is how nucleic acids, the basis of genetic material, were discovered.
Discovery of "hereditary molecules"
Modern genetics knows almost everything about nucleic acids, but, of course, this was not always the case. The first suggestion that chemicals could be somehow related to heredity was put forward only in the 19th century. At that time, the biochemist F. Miescher and the biologist brothers Hertwig were studying this problem. In 1928, the Russian scientist N. K. Koltsov, based on the results of research, suggested that all the hereditary properties of living organisms are encoded and placed in giant "hereditary molecules". At the same time, he stated that these molecules consist of ordered links, which, in fact, are genes. It was definitely a breakthrough. Koltsov also determined that these "hereditary molecules" are packed in cells into special structures called chromosomes. Subsequently, this hypothesis was confirmed and gave impetus to the development of science in the 20th century.
Development of science in the 20th century
The development of genetics and further research led to a number of equally important discoveries. It was found that each chromosome in a cell contains only one huge DNA molecule, consisting of two strands. Its numerous segments are genes. Their main function is that they encode information about the structure of enzyme proteins in a special way. But the implementation of hereditary information into certain traits proceeds with the participation of another type of nucleic acid - RNA. It is synthesized on DNA and makes copies of genes. It also transfers information to ribosomes, where it occurssynthesis of enzymatic proteins. The structure of DNA was elucidated in 1953, and RNA - between 1961 and 1964.
Since that time, molecular genetics began to develop by leaps and bounds. These discoveries became the basis of research, as a result of which the patterns of the deployment of hereditary information were revealed. This process is carried out at the molecular level in cells. Fundamentally new information about the storage of information in genes was also obtained. Over time, it was established how the mechanisms of DNA duplication occur before cell division (replication), the processes of reading information by an RNA molecule (transcription), and the synthesis of protein enzymes (translation). The principles of changes in heredity were also discovered and their role in the internal and external environment of cells was clarified.
Deciphering the structure of DNA
The methods of genetics have been intensively developed. The most important achievement was the decoding of chromosomal DNA. It turned out that there are only two types of chain sections. They differ from each other in the arrangement of nucleotides. In the first type, each site is original, that is, it has uniqueness. The second one contained a different number of regularly repeating sequences. They were called repetitions. In 1973, the fact was established that unique zones are always interrupted by certain genes. A segment always ends with a repeat. This gap encodes certain enzymatic proteins, it is by them that RNA "orients" when reading information from DNA.
First discoveries in genetic engineering
Emerging new methods of genetics led to further discoveries. A unique property of all living matter was revealed. We are talking about the ability to repair damaged areas in the DNA chain. They can arise as a result of various negative influences. The ability to self-repair has been called "the process of genetic repair". At present, many eminent scientists are expressing hopes, sufficiently backed by facts, that it will be possible to "snatch" certain genes from the cell. What can it give? First of all, the ability to eliminate genetic defects. Genetic engineering is the study of such problems.
Replication process
Molecular genetics studies the processes of transmission of hereditary information during reproduction. Preservation of the invariance of the record encoded in the genes is ensured by its exact reproduction during cell division. The whole mechanism of this process has been studied in detail. It turned out that immediately before cell division occurs, replication takes place. This is the process of DNA duplication. It is accompanied by an absolutely exact copying of the original molecules according to the rule of complementarity. It is known that there are only four types of nucleotides in the DNA strand. These are guanine, adenine, cytosine and thymine. According to the rule of complementarity, discovered by scientists F. Crick and D. Watson in 1953, in the structure of the double strand of DNA, thymine corresponds to adenine, and guanyl corresponds to the cytidyl nucleotide. During the replication process, each strand of DNA is copied exactly by substitution of the desired nucleotide.
Genetics –science is relatively young. The process of replication was only studied in the 1950s. At the same time, the enzyme DNA polymerase was discovered. In the 1970s, after many years of research, it was found that replication is a multi-stage process. Several different types of DNA polymerases are directly involved in the synthesis of DNA molecules.
Genetics and he alth
All information related to point reproduction of hereditary information during DNA replication processes is widely used in modern medical practice. Thoroughly studied patterns are characteristic of both he althy organisms and in cases of pathological changes in them. For example, it has been proven and confirmed by experiments that the cure of some diseases can be achieved with external influence on the processes of replication of genetic material and division of somatic cells. Especially if the pathology of the functioning of the body is associated with metabolic processes. For example, diseases such as rickets and impaired phosphorus metabolism are directly caused by inhibition of DNA replication. How can you change this state from the outside? Already synthesized and tested drugs that stimulate the oppressed processes. They activate DNA replication. This contributes to the normalization and restoration of pathological conditions associated with the disease. But genetic research does not stand still. Every year more and more data is received that helps not only to cure, but to prevent a possible disease.
Genetics and drugs
Molecular genetics deals with a lot of he alth issues. The biology of some viruses and microorganisms is such that their activity in the human body sometimes leads to a failure of DNA replication. It has also already been established that the cause of some diseases is not the inhibition of this process, but its excessive activity. First of all, these are viral and bacterial infections. They are due to the fact that pathogenic microbes begin to multiply rapidly in the affected cells and tissues. This pathology also includes oncological diseases.
Currently, there are a number of drugs that can suppress DNA replication in the cell. Most of them were synthesized by Soviet scientists. These drugs are widely used in medical practice. These include, for example, a group of anti-tuberculosis drugs. There are also antibiotics that inhibit the processes of replication and division of pathological and microbial cells. They help the body quickly cope with foreign agents, preventing them from multiplying. These drugs provide excellent treatment for most serious acute infections. And these funds are especially widely used in the treatment of tumors and neoplasms. This is a priority direction chosen by the Institute of Genetics of Russia. Every year there are new improved drugs that prevent the development of oncology. This gives hope to tens of thousands of sick people around the world.
Transcription and translation processes
After the experimentallaboratory tests on genetics and results on the role of DNA and genes as templates for protein synthesis, for some time scientists expressed the opinion that amino acids are assembled into more complex molecules right there in the nucleus. But after receiving new data, it became clear that this was not the case. Amino acids are not built on sections of genes in DNA. It was found that this complex process proceeds in several stages. First, exact copies are made from the genes - messenger RNA. These molecules leave the cell nucleus and move to special structures - ribosomes. It is on these organelles that the assembly of amino acids and protein synthesis take place. The process of making copies of DNA is called transcription. And the synthesis of proteins under the control of messenger RNA is “translation”. The study of the exact mechanisms of these processes and the principles of influence on them are the main modern problems in the genetics of molecular structures.
The importance of transcription and translation mechanisms in medicine
In recent years, it has become apparent that scrupulous consideration of all stages of transcription and translation is of great importance for modern he alth care. The Institute of Genetics of the Russian Academy of Sciences has long confirmed the fact that with the development of almost any disease, there is an intensive synthesis of toxic and simply harmful proteins for the human body. This process can proceed under the control of genes that are normally inactive. Or it is an introduced synthesis, for which pathogenic bacteria and viruses that have penetrated into human cells and tissues are responsible. Also, the formation of harmful proteins canstimulate actively developing oncological neoplasms. That is why a thorough study of all stages of transcription and translation is currently extremely important. This way you can identify ways to fight not only dangerous infections, but also cancer.
Modern genetics is a continuous search for the mechanisms of the development of diseases and drugs for their treatment. Now it is already possible to inhibit translation processes in the affected organs or the body as a whole, thereby suppressing inflammation. In principle, it is on this that the action of most known antibiotics, for example, tetracycline or streptomycin, is built. All of these drugs selectively inhibit translation processes in cells.
The importance of research into genetic recombination processes
Very important for medicine is also a detailed study of the processes of genetic recombination, which is responsible for the transfer and exchange of parts of chromosomes and individual genes. This is an important factor in the development of infectious diseases. Genetic recombination underlies the penetration into human cells and the introduction of foreign, more often viral, material into DNA. As a result, there is a synthesis on the ribosomes of proteins that are not “native” to the body, but pathogenic for it. According to this principle, the reproduction of whole colonies of viruses occurs in the cells. The methods of human genetics are aimed at developing means to combat infectious diseases and to prevent the assembly of pathogenic viruses. In addition, the accumulation of information on genetic recombination made it possible to understand the principle of gene exchangebetween organisms, which led to the emergence of genetically modified plants and animals.
The importance of molecular genetics for biology and medicine
Over the last century, discoveries, first in classical and then in molecular genetics, have had a huge, and even decisive, impact on the progress of all biological sciences. Medicine has advanced a lot. Advances in genetic research have made it possible to understand the once incomprehensible processes of inheritance of genetic traits and the development of individual human characteristics. It is also noteworthy how quickly this science grew from a purely theoretical into a practical one. It has become essential to modern medicine. A detailed study of molecular genetic regularities served as a basis for understanding the processes occurring in the body of both a sick and a he althy person. It was genetics that gave impetus to the development of such sciences as virology, microbiology, endocrinology, pharmacology and immunology.
