Living fossils can add basic principles to the theory of evolution, The field of evolutionary biology is characterized by heated discussion. But if there is a principle that is practically agreed upon by every specialist, it is natural selection taking place at the genome level.
The research team has now found the first convincing evidence that selection can also occur at the epigenome level. This term refers to a series of chemical “annotations” in the genome that determine whether, when, and to what extent genes are activated, and have been for tens of millions of years. and now the team found the Living fossils can add basic principles.
This unprecedented finding undermines conventional wisdom that in the geological period natural selection only affects variations in the sequence of the genome itself. The virus, which infects people with weakened immune systems and is responsible for about 20 percent of all HIV / AIDS deaths, has a specific epigenetic “label” on its DNA sequence that should be lost based on laboratory experiments and their statistical models. Species somewhere in the era of the dinosaurs.
However, research shows that this methylation label takes its name because it was created by a process that binds a molecule called a methyl group to a genome that has been attached for at least 50 million years, maybe even 150 million years from its last date.
This extraordinary performance of evolutionary resistance is made possible by unusual enzymes and rich doses of natural selection.
Although not observed in all forms of life, DNA methylation is also not uncommon. It occurs in all vertebrates and plants as well as in many fungi and insects. However, methylation is not found in some species.
Many of the organism models that form the basis of modern molecular biology laboratories originate from ancestors who have lost enzymes, which until the publication of this research were considered important for the spread of methylation from generation to generation.
The laboratory experiments of the researchers showed that the new methylation label occurred at a speed 20 times slower than the loss of methylation.
Obvious losses will exceed evolutionary time limits, and without de novo enzymes to compensate, the methylation of C. neoformans will disappear when dinosaurs disappear if selection pressure does not support the label.
When the researchers compared various strains of C. neoformans that were known to differ from each other nearly 5 million years ago, they found that not only all strains had DNA methylation, but areas similar to the methylation scar included the discovery, which showed that the methylation label of the site Certain genomics provide the survival benefits they have chosen.
The natural choice is to keep methylation at a much higher level than expected with a neutral profit and loss neutral process. This is an epigenetic equivalent of Darwinian evolution, researchers say.
Transposons, also called jumping genes, are pieces of DNA that can be extracted from one part of the genome and inserted into another part. If a transposon is inserted in the middle of a gene needed to survive, this gene may no longer function and cells can die.
Therefore, the silencing methylation transposition offers the obvious survival benefits needed to stimulate evolution. However, it remains to be seen how often this invaluable form of natural selection occurs in other species.