Multiple Genomic Landscapes of Recombination and Genomic Divergence in Wild Populations of House Mice—The Role of Chromosomal Fusions and Prdm9

Abstract

Chromosomal fusions represent one of the most common types of chromosomal rearrangements found in nature. Yet, their role in shaping the genomic landscape of recombination and hence genome evolution remains largely unexplored. Here, we take advantage of wild mice populations with chromosomal fusions to evaluate the effect of this type of structural variant on genomic landscapes of recombination and divergence. To this aim, we combined cytological analysis of meiotic crossovers (COs) in primary spermatocytes with inferred analysis of recombination rates based on linkage disequilibrium using single nucleotide polymorphisms. Our results suggest the presence of a combined effect of Rb fusions and Prdm9 allelic background, a gene involved in the formation of meiotic double strand breaks and postzygotic reproductive isolation, in reshaping genomic landscapes of recombination. We detected a chromosomal redistribution of meiotic recombination towards telomeric regions in metacentric chromosomes in mice with Robertsonian (Rb) fusions when compared to non-fused mice. This repatterning was accompanied by increased levels of CO interference and reduced levels of estimated recombination rates between populations, together with high levels of genomic divergence. Interestingly, we detected that Prdm9 allelic background was a major determinant of recombination rates at the population level, whereas Rb fusions showed limited effects, restricted to centromeric regions of fused chromosomes. Altogether, our results provide new insights into the effect of Rb fusions and Prdm9 background on meiotic recombination.

The Role of Retinoic Acid in Spermatogenesis and Its Application in Male Reproduction

“…During meiosis, MEIOSIN is also a downstream target of RA, and RA can activate MEIOSIN expression [66]. RA activates key genes involved in meiosis through its receptors RARs and RXRs, such as Msh5, Prdm9 and Sycp3 [67,68]. RA can also rapidly activate protein kinase c and transmit the activation signal to CREB through the ras/erk/rsk pathway without the pathway of RA-related receptors [69].…”

“…At late meiotic stages in spermatogenic cells, RA activates vital genes involved in the meiotic process, such as Msh5, Prdm9, and Sycp3, via their receptors RARs and RXRs [83]. The proteins encoded by these genes play essential roles in late meiosis, with Msh5 involved in chromosome pairing and recombination, Prdm9 in chromosome recombination exchange, and Sycp3 in chromosome pairing and recombination [67,68]. In terms of transcriptional regulation, RA can rapidly activate protein kinase c and transmit the activation signal to CREB through the ras/erk/rsk pathway without the pathway of RA-related receptors [69].…”