Cytogenetics of hybrid male sterility in the European house mouse

https://www.natur.cuni.cz/fakulta/uchazeci/doktorske-studium/prijimaci-rizeni

Supervisor: prom. biol. Jaroslav Piálek, CSc. (jpialek@ivb.cz)

Laboratory based crosses between two house mouse subspecies, Mus m. musculus (Mmm) a M. m. domesticus (Mmd), readily document the presence of F1 sterile males. This sterility is controlled by epistatic interaction between 2 loci, the Prdm9 gene on chromosome 17 and X-linked locus Hstx, and heterozygosity at homologous autosomal chromosomes. The two loci control pleiotropically also meiotic recombination. Mechanistically, F1 hybrid sterility is caused by increased asynapsis resulting to meiotic arrest and elimination of meiocytes by apoptosis. Recently is has been demonstrated that Prdm9 gene displays extremely high allelic polymorphism; however, it remains unknown which genetic polymorphism results in sterility and at which stage of meiosis is spermatogenesis arrested. The aim of the PhD study will be cytogenetic analysis of spermatogenesis in sterile hybrids primarily via immunostaining of proteins participating in a repair of double strand breaks in chromatid crossovers to infer whether (1) various allelic sterility combinations in Prdm9 and Hstx1/2 loci are arrested at the same stage of meiosis, and (2) these allelic variants also affect recombination and asynapsis rates in comparison with fertile combinations. Sterile F1 combinations will be derived from 43x43 pairwise intersubspecific crosses of wild-derived strains from the Western Palearctic (housemice.cz) and will be already available at the start of PhD.

Laboratory work will be realized in a research facility of the Institute of Vertebrate Biology, Czech Academy of Sciences, in Studenec. The study is supported by the Czech Science Foundation (grant 19-12774S) in 2019–2021. The project provides also salary for half-time employment in addition to scholarship.