Genetics is a science that studies the patterns of transmission of characters from parents to offspring. This discipline also examines their properties and ability to change. Moreover, special structures — genes — act as information carriers. Currently, 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 property of all organisms to transmit during reproduction their external and internal signs to offspring. Classical genetics also studies variability. It is expressed in instability of signs. These changes are accumulating from generation to generation. Only due to such inconstancy can organisms adapt to changes in their environment.
Hereditary information of organisms is contained in genes. They are currently being examined in terms of molecular genetics. Although these concepts arose long before the appearance of this section.
The terms "mutation", "DNA", "chromosomes", "variability" have become known in the process of numerous studies. Now the results of centuries-old experiments seem obvious, but once it all started with random crosses. People sought to get cows with large milk yields, larger pigs and sheep with thick wool. These were the first, not even scientific, experiments. However, it was precisely these prerequisites that led to the emergence of such a science as classical genetics. Until the 20th century, crossbreeding was the only known and affordable 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 laws 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 maintain the basic features of the structure of their body, as well as the flow patterns of the metabolic processes and responses to the effects of 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 subsequent generations during the fertilization process. The discovery of these substances and their subsequent study was made possible by studying the structure of cells at the chemical level. Thus, nucleic acids, the basis of genetic material, were discovered.
The discovery of "hereditary molecules"
Modern genetics knows almost everything about nucleic acids, but, of course, this was not always the case. The first assumption that chemicals may be somehow related to heredity was advanced only in the 19th century. At that time, the biochemist F. Misher and the biological brothers Gertwigi were studying this problem. In 1928, the domestic scientist N.K. Koltsov, relying on research results, suggested that all the hereditary properties of living organisms are encoded and placed in giant "hereditary molecules." However, he said that these molecules consist of ordered units, which, in fact, are genes. This 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.
The development of science in the 20th century
The development of genetics and further research has led to a number of equally important discoveries. It was found that each chromosome in the cell contains only one huge DNA molecule, consisting of two strands. Its numerous segments are genes. Their main function is that they specifically encode information on the structure of protein enzymes. But the realization of hereditary information in certain signs proceeds with the participation of another type of nucleic acid - RNA. It is synthesized into DNA and takes copies of genes. It also transfers information to the ribosomes, where the synthesis of enzyme proteins takes place. The structure of DNA was elucidated in 1953, and RNA in the period from 1961 to 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 development of hereditary information were revealed. This process is carried out at the molecular level in the cells. Fundamentally new information was also obtained on the storage of information in genes. Over time, it was established how the mechanisms of DNA doubling before cell division (replication), the processes of reading information by an RNA molecule (transcription), and the synthesis of protein-enzymes (translation) occur. The principles of changing heredity were also discovered and their role in the internal and external environment of cells was clarified.
Decoding the DNA structure
Genetics methods have been intensively developed. The most important achievement was the decoding of chromosomal DNA. It turned out that there are only two types of sections of the chain. They differ from each other by the arrangement of nucleotides. In the first type, each site is unique, that is, it is unique. The second contained a different number of regularly repeated sequences. They were called repeats. In 1973, it was established that unique zones are always interrupted by certain genes. A line always ends with a repeat. This gap encodes certain enzymatic proteins; it is precisely along these lines that RNA “orientates” when reading information from DNA.
First discoveries in genetic engineering
Emerging new methods of genetics entailed 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 occur as a result of various negative influences. The ability to self-repair was called the "process of genetic repair." Nowadays, many eminent scientists are expressing enough evidence-based hopes for the ability to “grab” certain genes from the cell. What can it give? First of all, the ability to eliminate genetic defects. The study of such problems is engaged in genetic engineering.
Replication process
Molecular genetics studies the transmission of hereditary information during reproduction. Preservation of the immutability of the record encoded in the genes is ensured by its accurate reproduction during cell division. The whole mechanism of this process is studied in detail. It turned out that just before the division in the cell, replication takes place. This is the process of doubling DNA. It is accompanied by 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 a DNA strand. These are guanine, adenine, cytosine and thymine. According to the complementarity rule, discovered by scientists F. Crick and D. Watson in 1953, thymine corresponds to adenine in the structure of a double strand of DNA, and guanyl to a cytidyl nucleotide. During the replication process, each DNA strand is precisely copied by substituting the desired nucleotide.
Genetics is a relatively young science. The replication process was studied only in the 50s of the 20th century. Then the DNA polymerase enzyme was discovered. In the 70s, after 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 Health
All information related to the point reproduction of hereditary information during DNA replication processes is widely used in modern medical practice. Thoroughly studied patterns are characteristic of both healthy organisms and in cases of pathological changes in them. For example, it has been proved and confirmed by experiments that the cure of certain diseases can be achieved with external influences on the replication of genetic material and the 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 inhibited 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 being received that helps not only to cure, but to prevent a possible disease.
Genetics and drugs
Molecular genetics deals with so many health 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 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 in the affected cells and tissues at an accelerated rate. Oncological diseases also belong to this pathology.
Currently, there are a number of drugs that can inhibit 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-TB drugs. There are antibiotics that suppress the processes of replication and division of pathological and microbial cells. They help the body quickly cope with foreign agents, preventing them from multiplying. Such medications provide an excellent therapeutic effect in most serious acute infections. And these drugs are especially widely used in the treatment of tumors and neoplasms. This is the priority area chosen by the Institute of Genetics of Russia. Each year, new improved drugs appear that impede the development of oncology. This gives hope to tens of thousands of sick people around the world.
Transcription and translation processes
After experimental laboratory tests were carried out on genetics and results were obtained on the role of DNA and genes as matrices 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 is not so. 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 — informational RNAs — are taken from the genes. These molecules come out of the cell nucleus and move to special structures - ribosomes. It is on these organelles that amino acid assembly and protein synthesis take place. The process of obtaining copies of DNA is called "transcription". And protein synthesis under the control of messenger RNA is “translation”. Studying 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 health care. The Institute of Genetics of the Russian Academy of Sciences has long confirmed the fact that with the development of almost any disease, an intense synthesis of toxic and simply harmful proteins to the human body is noted. This process can occur under the control of genes that are inactive in the normal state. Or it is an introduced synthesis, for which pathogenic bacteria and viruses that penetrate into human cells and tissues are responsible. The formation of harmful proteins can also stimulate actively developing cancerous tumors. That is why a thorough study of all stages of transcription and translation is currently extremely important. So you can identify ways to deal not only with dangerous infections, but also with cancer.
Modern genetics is a continuous search for mechanisms for the development of diseases and drugs for their treatment. It is now possible to inhibit translation processes in affected organs or the body as a whole, thereby suppressing inflammation. In principle, this is the basis for the action of most known antibiotics, for example, tetracycline or streptomycin. All of these drugs selectively inhibit translation processes in cells.
The Importance of Studying Genetic Recombination Processes
A detailed study of the processes of genetic recombination, which is responsible for the transfer and exchange of chromosome regions and individual genes, is also very important for medicine. This is an important factor in the development of infectious diseases. Genetic recombination is the basis of penetration into human cells and the introduction of alien, often viral, material into the DNA. As a result, the synthesis on the ribosomes occurs not of proteins "native" to the body, but pathogenic for it. According to this principle, the reproduction in cells of entire colonies of viruses occurs. Methods of human genetics are aimed at developing means of combating 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 exchange between organisms, which led to the emergence of genomically modified plants and animals.
The Importance of Molecular Genetics for Biology and Medicine
Over the past century, discoveries first in classical and then in molecular genetics have had a huge, and even decisive influence on the progress of all biological sciences. Particularly stepped forward medicine. The success of genetic research made it possible to understand the once incomprehensible processes of inheritance of genetic traits and the development of individual characteristics of a person. It is also noteworthy how quickly this science grew from purely theoretical to practical. It has become critical to modern medicine. A detailed study of molecular genetic patterns served as the basis for understanding the processes occurring in the body of both a sick and a healthy person. It was genetics that gave impetus to the development of such sciences as virology, microbiology, endocrinology, pharmacology and immunology.