Why the mechanisms of biological evolution are still not revealed?
Keywords:mechanism of evolution, biological variability, noncoding DNAs, heterochromatin, origin of species.
Since the days of Darwin, it is generally accepted that biological evolution rests on three pillars: variability, inheritance and selection. It is believed that main sources of variability, mechanisms of inheritance and forms of natural selection have been clarified. Nevertheless, for more than 150 years since the publication of “Origin of Species” no consensus as to the mechanisms of evolution emerged. It is highly likely that the main obstacle in elucidating the mechanisms of evolution is the incompleteness of our knowledge regarding the sources of biological variability. The following sources of variability are universally recognized: gene mutations, gene recombination during meiosis and gene duplication. However, the role of the non-genic part of the genome, which makes up the vast majority of DNA in eukaryotes, remains unclear. For example, in human chromosomes, about 98% of DNA is represented by non-coding nucleotide sequences (ncDNAs). Although no one excludes their possible role in evolution, nevertheless, studies aimed at elucidating the participation of the non-genic part of the genome in variability, inheritance and selection are extremely small. The possible role of ncDNAs in the origin of biological variability in the eukaryotic genome and their evolution is discussed.