DNA is a deoxyribonucleic acid that ensures the preservation and transmission of genetic information. Information about the structure of RNA and all body proteins is encrypted in its structure. This structure was discovered by the Swiss I.Mishler in 1869.
At first, the true properties of DNA were unknown. It was believed that she was responsible for the preservation of phosphorus in the body, and they were not even aware of its properties to transmit information, since proteins were traditionally considered carriers of hereditary information. Only in 1944, after a series of experiments on the transformation of bacteria, it was found out what DNA was, and its basic functions were also determined. After 1952, information about this molecule expanded - it became known that it was the main carrier of information on the structure of the genotype (the totality of genes in the body), but at that time they still did not know anything about its structure, the
DNA structure was not deciphered.
Its molecular structure was deciphered in 1953 by James Watson and Francis Crick. They determined what DNA is — a double helix molecule made up of deoxyribose and phosphate groups that are bound by nitrogen bases — adenine, cytosine, guanine, and thymine.
It should be noted that the combination of these bases has a clearly defined order - adenine combines only with thymine, and guanine with cytosine, which ensures correct and clear self-reproduction of the DNA molecule by the principle of complementarity with one of its daughter helices.
Such a clear definition of the molecular structure made it possible to better understand what DNA is - a structure that preserves the genetic code and is the basis of the heredity of all living organisms, including eukaryotes and some viruses.
The genetic code is stored as a specific nucleotide sequence. So, each amino acid of a protein is encoded by three nucleotides, and the sequence of acids is a gene.
With any changes in the structure of DNA, point or gene mutations occur. Point mutational changes are a violation of the molecular structure, which is easily detected by biochemical or hybridological analysis. Gene mutations appear when nucleotide sequence changes, which is the result of processes such as the transition, transversion, insertion or loss of individual pairs of nitrogen bases that disrupt the functioning and properties of DNA.
If such structural changes lead to a distortion of important sections of the polypeptide, then serious disorders occur in the body that determine not only the development of organisms, but also their death. So, mutations can occur even during fetal development, which causes the birth of dead or non-viable children. In addition, such disorders underlie many congenital malformations that can be transmitted to subsequent generations.
To summarize the above, we can conclude as to what DNA is - this is an extremely important structure of genetic information, which is the main component of chromosomes. In addition, DNA is an acid that is responsible for the implementation of hereditary information and the functioning of living organisms.