Genetics - from antiquity to the present day

Genetics is a field of biology studying genes, laws of heredity and the principles of the variability of organisms. In principle, to some extent, the roots of genetics can be traced back to the dawn of the emergence of human civilization, when mankind accidentally discovered the fact that living things can inherit the traits of their ancestors and, of course, their parents. The advantage of this fact was revealed very quickly, and thus a selective breeding of both cereal crops and animals appeared. However, modern genetics begins in the middle of the nineteenth century, with the works of Gregor Mendel. Even though the physical foundations of Mendel's heredity were unknown, he managed to note that organisms inherit certain traits through special discrete units of heredity. These are the units we today call genes.

Essentially, genes are regions in DNA, and DNA is a molecule consisting of four different types of nucleotides, the sequence of which is genetic information inherited by organisms. The genetic code, in turn, is the relationship between the sequence of nucleotides and the sequence of amino acids that are responsible for the functions of the protein.

However, genetics, although it plays an extremely significant role both in the appearance itself, and in the development, functioning and behavior of an organism, is not the only one determining, so to speak, the "final result" of development. In addition to genetics itself, the conditions in which the development of the organism takes place are also involved. Relatively speaking, heredity can play an important role in the formation, for example, of high growth, but the characteristics of the environment, nutrition, the amount of physical activity and even the performance of specific exercises - all this can significantly affect the indicated sign (growth).

A number of diseases can be transmitted by exactly the same model. Such diseases are called "hereditary diseases", or diseases, the emergence and development of which is caused by cell defects. It should not be confused with polyethological diseases and a narrower group of diseases of the gene group. How is genetic disease inherited? At the heart of hereditary diseases is nothing else than mutations transmitted by inheritance of information - whether it be gene, chromosomal or mitochondrial mutations. Hereditary diseases number more than six thousand.

According to statistics, about five or six children from a hundred newborns are born with a genetically determined disease, usually with a disease with a genetic predisposition. It should be noted that the number of such diseases can include developmental defects, as well as certain violations in the intellectual development of the child. However, the same number includes other hereditary diseases, which could both arise for the first time, and be inherited from the parents (or from one of them). The probability of the birth of a child with a genetically determined disease depends on a number of facts, among which:

1. Age of parents. As with age, more and more minor mutations accumulate in the cells, the risk of having a child with a genetic anomaly increases with age;

2. Closely related. Relatives can be carriers of the same sick genes, which will uniquely adversely affect the offspring;

3. Previously encountered in the family genetic abnormality. This can be both in the form of chronic family illnesses, and in the presence of already born sick children;

4. Belonging to certain ethnic groups.

Alas, the best way to treat genetic diseases is to prevent them, which is considered genetic counseling and genetic testing - even before the conception of the child.