Hybrid male sterility in the house mouse

Hybrid sterility is one of the postzygotic reproductive barriers that can prevent gene flow between diverging populations. Identification of sterility genes and their function is consequently demanded for understanding of processes that can ultimately lead to speciation. The sterility locus Hst1 (Hybrid sterility-1) on chromosome 17 was originally described in hybrid progeny delivered in intersubspecific crosses between wild Mus musculus musculus, sampled at localities in Prague, and two classical laboratory strains C57BL/10 (producing sterile hybrid males) and C3H (producing fertile hybrid males), derived from M. m. domesticus; Hst1 was defined by the presence of polymorphism in the domesticus genome. We confirmed that Hst1-related sterility is polymorphic in natural allopatric populations and noted additional polymorphic genes affecting hybrid sterility in crosses between wild M. m. musculus from Studenec and C57BL/10. To determine the genetic basis underlying male fertility, we derived two wild-origin musculus strains, STUS and STUF, producing alternative phenotypes in crosses with C57BL/10 mice (sterile and fertile males, respectively). From the cross of musculus (STUS × STUF)F1 females and C57BL/B10 we obtained both fertile and sterile hybrid males. Infertile hybrid males suffered from significantly..