Zakia Bayguzhina
DNA and Bioinformatics

Don’t judge each day by the harvest you reap, but by the seeds you plant.

Robert Louis Stevenson (1850–1894)

In the modern world, a huge amount of information has already accumulated, and it requires systematization and thoughtful analysis. This is necessary for a better understanding and further study of the results obtained. Most importantly, such an approach helps to find practical applications for discoveries that can be made through the analysis of collected data.

Therefore, information technology has become a real salvation in the process of understanding accumulated knowledge. At the same time, this opens up new horizons in our understanding of the world around us. This is especially true in biology, where a large amount of material has already been collected and the time has come to analyze scientific knowledge in this field.

In this case, we turn to one branch of biology – molecular biology. And, of course, DNA, often referred to as the “molecule of life,” is of particular interest.

The structure of the DNA molecule is well known, largely due to the work of Francis Crick (1916–2004) and James Dewey Watson (1928–2025), who published an article on the spatial structure of DNA in the journal Nature on April 25, 1953.

The hereditary information stored in the DNA molecule is well protected. The nitrogenous bases are hidden inside the molecule, while the chains consisting of phosphoric acid and deoxyribose residues form a strong external backbone.

Various types of DNA are currently known, but in this case we are interested in the double-stranded B-form, which is most commonly found in living cells.

The structure of DNA can be described as follows: two antiparallel polynucleotide chains are twisted around a common axis. On the periphery of the molecule are carbohydrate–phosphate chains, while nitrogen-containing heterocycles are located inside. DNA contains four nitrogenous bases: purines – adenine and guanine, and pyrimidines – thymine and cytosine. However, there are exceptions. For example, some viruses contain another pyrimidine derivative – uracil.

The nitrogenous bases of one chain pair with specific bases of the other chain according to Chargaff’s rule: adenine pairs with thymine, and guanine pairs with cytosine. This arrangement is known as complementarity. The pairing of nitrogenous bases occurs via hydrogen bonds.

Scheme of the arrangement of complementary nitrogenous bases in DNA

One of the DNA strands is involved in the process of transcription, that is, the reading of genes for the synthesis of proteins necessary for the vital functions of the organism.

This strand is called the coding strand.

In this strand, specific regions of nucleotide sequences correspond to the amino acid sequence of a protein.

The other strand is used for DNA replication during cell division.

Interestingly, only 1–2% of DNA contains hereditary information.

The remaining part is sometimes called “junk DNA.” But that’s impossible! Nature is organized in such a way that nothing in it is superfluous or unnecessary. Therefore, this part of DNA also performs a specific function. And this function is called the energetic function, meaning that DNA gives the energy required for carrying out biochemical reactions.

As is well known, the DNA molecule contains the most important information, represented in the form of genes. We are particularly interested in the human genome.

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