• PMID: 30333190
• Gene Name: Prdm9
• Condition: Male infertility
• Association: Associated
• Sex: Male
• Infertility type: Male infertility
• Other associated phenotypes: Male infertility

Genetic Dissection of Hybrid Male Sterility Across Stages of Spermatogenesis

Schwahn DJ, Wang RJ, White MA, Payseur BA.

Hybrid sterility is a common form of reproductive isolation between nascent species. Although hybrid sterility is routinely documented and genetically dissected in speciation studies, its developmental basis is rarely examined, especially in generations beyond the F(1) generation. To identify phenotypic and genetic determinants of hybrid male sterility from a developmental perspective, we characterized testis histology in 312 F(2) hybrids generated by intercrossing inbred strains of Mus musculus domesticus and M. m. musculus, two subspecies of house mice. Hybrids display a range of histologic abnormalities that indicate defective spermatogenesis. Among these abnormalities, we quantified decreased testis size, reductions in spermatocyte and spermatid number, increased apoptosis of meiosis I spermatocytes, and more multinucleated syncytia. Collectively, our phenotypic data point to defects in meiosis I as a primary barrier to reproduction. We identified seven quantitative trait loci (QTL) controlling five histologic traits. A region of chromosome 17 that contains Prdm9, a gene known to confer F(1) hybrid male sterility, affects multinucleated syncytia and round spermatids, potentially extending the phenotypic outcomes of this incompatibility. The X chromosome also plays a key role, with loci affecting multinucleated syncytia, apoptosis of round spermatids, and round spermatid numbers. We detected an epistatic interaction between QTL on chromosomes 17 and X for multinucleated syncytia. Our results refine the developmental basis of a key reproductive barrier in a classic model system for speciation genetics. CI - Copyright © 2018 by the Genetics Society of America. FAU - Schwahn, Denise J AU - Schwahn DJ AD - Research Animal Resources Center, University of Wisconsin-Madison, Wisconsin 53726. FAU - Wang, Richard J AU - Wang RJ AUID- ORCID: 0000-0002-8889-4269 AD - Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53706. FAU - White, Michael A AU - White MA AD - Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53706. AD - Department of Genetics, University of Georgia, Athens, Georgia 30602.