Double-bottom DNA

Physicists have confirmed the presence of a second layer of information hidden in human DNA

Evgenia Efimova, Vesti

Everything that makes a person what he is is embedded in his DNA: from his appearance to hereditary diseases. Moreover, recent studies have shown that DNA even records whether a person will achieve financial success, and the age at which he will lose his virginity.

However, many scientists have long believed that a person is not only, so to speak, the product of his own genetic code, but also "mechanical commands" that are determined by how the DNA molecule is folded inside human cells. Now theoretical physicists from the Netherlands have confirmed that this second "layer" of information really exists.

Recall that proteins are the building material of our body. The sequence of the four main nitrogen-containing nucleic bases (A, G, C and T) in the human genetic code of DNA determines which proteins are produced in the body and in what quantity.

So, for example, if a person has brown eyes, it is for the reason that the sequence of "letters" in DNA encodes proteins that "create" brown eyes.

But despite the fact that every human cell contains the same DNA sequence, differences in organs (and their work) suggest that there is some other process that affects how information is formed inside cells.

Human DNA is tightly packed in the nucleus of cells, since each DNA molecule can be stretched by about two meters.

In the 1980s, scientists suggested that the mechanical properties of DNA dictate exactly how its "thread" is folded in a cell and, as a result, the genetic code changes. All this provides an additional layer of information at the top of the sequence A, G, C and T in the double helix structure of DNA.

A team of researchers led by Helmut Schiessel from the Institute of Physics in Leiden applied computer modeling to test this hypothesis. As a result, scientists have found convincing evidence that such "mechanical commands" exist in reality.

Scientists transmitted randomized (randomly selected) mechanical signals to DNA strands in two organisms – baking yeast and yeast of the genus Schizosaccharomycetes – and found that DNA molecules are folded differently in them.

Experts explain that mutations in DNA thus have a double effect to change two different things: a certain sequence of genetic letters of a protein or the mechanical structure of DNA. In the second case, it will determine how the genetic code will be read, as well as the type and amount of proteins that will be produced.

The results of the study are published in the scientific publication PLOS One (Eslami-Mossallam et al., Multiplexing Genetic and Nucleosome Positioning Codes: A Computational Approach).

Portal "Eternal youth" http://vechnayamolodost.ru  14.06.2016