A.V. Khalyavkin

A popular theory of aging associates it with the age-related changes of cells due to the shortening of chromosomes because of under-replication DNA in telomeric regions of linear chromosomes. However, linearity of chromosomes not necessarily means the linear organization of their DNA. Moreover, there is reason to believe that the DNA strands with free ends the double helix is an artifact of the methods of its isolation and the norm is always a ring. In super-coiled form a ring of DNA has a rhabdoid form - a simplified analogue of a linear chromosome, complete with histone and non-histone proteins etc. Even a linear molecule of DNA of some viruses has "sticky" ends, which, uniting in pre-replicative period, form circular DNA. Hairpins on the ends of linear DNA of other viruses provide a one-chained ring at a divergence of complementary chains. There are hypotheses about the circular organization of the hereditary material in higher eukaryotes, the structure of which has not yet been clarified. In any case, it is conceivable that the shortening of telomere regions of chromosomes is not a passive process associated with steric peculiarities of their structure and the process is actively regulated positive (telomerase, tankyrase, etc.) and negative (TRF1, TRF2 and other) factors, in accordance with needs of the body and under his direct control. Telomeres, as well as many structures of the body, have more than one function. For example, they attributed the function of limiting the number of cell divisions. Telomeres are crucial for proper implementation of meiosis. Chromosomes are attached to the nuclear membrane just by telomeres. Perhaps intra-chromosomal telomeric sequences contribute to the formation of macrostructure chromosome and its stability. This is evidenced by quadruplexes DNA both on the distal parts of chromosomes and on telomeric sequences at sites scattered along the entire length of the chromosome. Just the same intra-chromosomal telomeric DNA sequences can serve as additional anchoring zones giant chromosomes.

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