The evolution of species through that of their genome - examples of genes involved in mammalian reproduction

Genes involved in reproduction exhibit a particularly fast phylogenetic evolution. This rapid evolution could be illustrated by birth of genes in mammals as for numerous genes exclusively expressed in oocytes (KHDC1, NALP...). It can also be illustrated by death of genes by pseudogenization (by transformation into a pseudogene, although all pseudogenes do not have similar production mechanisms), as for genes encoding zona pellucida proteins that are progressively lost during evolution of vertebrates. This evolution can also be illustrated by positive selection as for genes encoding Odorant Bindng Proteins or GPR50, a member of melatonin receptor family. Most of these events most likely appeared randomly; they lead to living species adapted to the environment of the moment, and have been conserved. The description of all of these events and of their molecular mechanisms is one of the next future challenges, in particular with whole genome sequences and mathematical tools used in phylogeny. (C) 2019 Published by Elsevier Masson SAS on behalf of Academie Nationale De Medecine.