The role of retroelements in the evolution of animal genomes
aLomonosov Moscow State University, Faculty of Biology, Department of Genetics
Leninskiye Gory, 1/12, Moscow, 119234 Russia
*e-mail: lidia_nefedova@mail.ru
Retroelements (retrotransposons and endogenous retroviruses) are a class of mobile genetic elements that is widely represented in various groups of eukaryotes. It is believed that most of the retroelements present in the genome do not significantly affect the host organism, which, in the process of co-evolution with retroelements, produces various mechanisms for controlling their transposition. But even retrotroelements deprived of transpositional activity can play a significant role in evolution, contributing to the formation of new adaptive mechanisms, which, in turn, are caused by the formation of new genetic networks. The process in which the body adapts individual sequences of retroelements is called molecular domestication. Exaptation implies the formation of new genetic structures and functions, which, as a rule, appear as a result of the long evolution of domesticated sequences of mobile elements. For three key genes of retrotransposons/endogenous retroviruses (gag, pol, and env), cases of domestication are known. The phenomenon of domestication/exaptation testifies to the fundamental role that retroelements play in the evolution of the genome and the significant evolutionary benefit of the presence of retroelements in the genome despite the fact that their transposition activity can be accompanied by negative effects at the level of an individual organism.
