Génétique humaine et Embryologie

Epigenetics and Evolutionary Mechanisms

Abstract

Tomoko Ohta

In this article, an attempt to incorporate recent knowledge of epigenetics into the evolutionary theory is presented. As our interest is to clarify evolutionary mechanisms at the molecular level and to connect them to phenotype evolution, the interplay of drift and selection (near-neutrality) on molecular evolution is briefly reviewed. Epigenetic phenomena are partly controlled by genetic systems via chromatin structure, and special attention has been paid to the dynamic evolution of three gene families which encode chromatin components. These gene families are characterized by rapid birth and death of gene copy members, and weak diversity enhancing selection. Also the protein products contain disordered domain that provides flexible chromatin structure. The near-neutrality concept may be extended to their evolution. Here drift, selection and epigenetics become inseparable, and their interplay is thought to have been needed for the evolution of complex gene regulatory systems.