HOUSE MICE AS MODELS IN SYSTEMATIC BIOLOGY

We evaluated the house mouse (Mus musculus species complex) and its laboratory descendents as models for three aspects of systematic biology: hybrid zone biology, chromosomal evolution and speciation, and tests for methods of phylogenetic reconstruction. The taxonomy and genetic relationships of the species in the complex are summarized. The comparative phylogenetic method was used to illucidate biogeographical, ecological, and chromosomal events in the group. Hybridization in house mice was evaluated with respect to the emerging discipline of hybrid zone biology. Inter- and intraspecific contact zones are described and compared. Zone-specific electrophoretic alleles, new metacentric chromosomes, and increased levels of parasitism are explained as consequences of genome disruption. The interspecific zone is widest in the area of most recent contact between species. Variation in the widths of individual clines is discussed. Chromosomal evolution is proceeding along alternative paths in different commensal lineages of house mice. A karyotypic revolution occurred within the species M. domesticus that led to the reproductive isolation between two local populations. The recency of this karyotypic revolution permits a study of how Robertsonian populations evolve and an evaluation of whether the stasipatric model of speciation is a good explanation for this case. The genealogical history of the inbred strains of mice is well known, and this information has been used to test how faithfully different kinds of data and different kinds of analytical techniques recreate the known phylogeny. Molecular data recapture the correct phylogeny better than do morphological data, and the commonly used analytical methods are all equally robust in producing this phylogeny.