Abstract
In this lecture and the following one, we have focused on a second process at the origin of genetic novelties : meiotic recombination, which generates new combinations of alleles. Despite the fundamental importance of recombination for any sexually reproducing species, the distribution of recombination events along the genome differs considerably from one species to another, notably between humans and chimpanzees. Since 2010, we know that this rapid evolution is largely due to differences in the binding domain of the PRDM9 gene. In species with PRDM9, including most mammals, the specificity of PRDM9 binding to DNA and the position of hotspots are evolving very rapidly. By contrast, in species without PRDM9, such as birds, recombination is high near promoters and in particular CpG islands, and even at the fine kilobase scale, recombination rates appear to be conserved over long periods.
