Epigenetic factors and regulation of meiotic recombination in mammals

Abstract

During meiosis, recombination is induced to promote connections between homologous chromosomes, thereby ensuring faithful chromosome segregation. These connections result from reciprocal recombination events or crossovers. Absence or defects of recombination can lead to genome instability, chromosome nondisjunction, aneuploid gametes, or reduced fertility. Recombination events are therefore highly regulated through mechanisms that are still poorly understood. The role of epigenetic modifications in meiotic recombination is suggested by several observations, particularly by the differences between male and female recombination as well as by interindividual variations in crossover rates. In this review, we describe features of meiotic recombination that might involve epigenetic controls. We then present the epigenetic marks and modifiers known to occur or to play a role during meiotic prophase when recombination takes place. Direct evidence of a functional link between histone modifications and recombination is highlighted by a recent analysis of the distribution of recombination showing that the protein PRDM9 targets chromatin modifications to specific sites in the genome where initiation of meiotic recombination takes place. © Springer-Verlag Berlin Heidelberg 2011.