Abstract
During meiosis, DNA double-strand breaks initiates homologous recombination at specific loci called hotspots. In many mammals, their localization corresponds to specific DNA sequences bound by the zinc finger (ZnF) array of PRDM9. A remarkable property of PRDM9 is the high diversity and fast evolution of its ZnF domain. The consequence is the fast evolution of recombination map for species having a PRDM9 for hotspot localisation. PRDM9 appears in the last common ancestor of metazoans but its partial or complete loss have been surprisingly reported in many taxa. Species lacking a full-length PRDM9 have evolutionary stable hotspots that are located near promoter-like regions, that are evicted by PRDM9. The involvement of PRDM9 in meiotic recombination has not been yet explored outside vertebrate species, one reason being that invertebrate model species (drosophila, nematode) have no PRDM9. Here, we propose to fill these gaps by investigating PRDM9 function in meiotic recombination in four closely-related species of freshwater snails for which we recently identified full-length PRDM9 conservation by exploring their recently published genome assemblies.We started to investigate PRDM9 ZnF diversity in these species. Hypervariable amino-acid at positions contacting DNA and diversity in number and order of ZnF between individuals and populations indicate a probable involvement of PRDM9 in specifying recombination hotspot. This hypothesis will be further investigated by using complementary approaches such as mapping DNA double-strand breaks in meiocytes.