Experimental hybridization and an evaluation of the fertility of some forms of the house mouse supraspecies complex Mus musculus (Rodentia, Muridae)

Abstract

The degree of development of the mechanisms of postcopulatory isolation was evaluated on the basis of experimental hybridization of representatives of three subspecies of M. musculus (M. m. musculus, M. m. wagneri, and M. m. gansuensis) and remote populations of the subspecies M. m. musculus. Experimental crosses between the different subspecies and populations indicated the presence of initial stages of postcopulatory reproductive isolation between some forms of house mice. In a number of crosses conducted between different populations and subspecies of M. musculus, asymmetry was observed. In one variant of mating, M. m. musculus (male) × M. m. wagneri (female), a reduced intensity of breeding and nonviability of pups were observed. A decrease in the intensity of reproduction was found in all variants of crosses that used male M. m. musculus from the city of Ishim. These data are assumed to confirm the previous assumption about the hybrid origin of mice inhabiting that city. The results confirm a significant level of divergence of the subspecies M. m. musculus and M. m. wagneri. Thus, initial stages both of post- and precopulatory isolation mechanisms between M. m. wagneri and M. m. musculus were shown.