HOUSE MICE AS MODELS IN SYSTEMATIC BIOLOGY

We evaluated the house mouse (Mus musculus species complex) and its la boratory 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 compar ative phylogenetic method was used to illucidate biogeographical, ecol ogical, and chromosomal events in the group. Hybridization in house mi ce was evaluated with respect to the emerging discipline of hybrid zon e biology. Inter- and intraspecific contact zones are described and co mpared. Zone-specific electrophoretic alleles, new metacentric chromos omes, 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 indiv idual clines is discussed. Chromosomal evolution is proceeding along a lternative paths in different commensal lineages of house mice. A kary otypic revolution occurred within the species M. domesticus that led t o the reproductive isolation between two local populations. The recenc y of this karyotypic revolution permits a study of how Robertsonian po pulations evolve and an evaluation of whether the stasipatric model of speciation is a good explanation for this case. The genealogical hist ory of the inbred strains of mice is well known, and this information has been used to test how faithfully different kinds of data and diffe rent kinds of analytical techniques recreate the known phylogeny. Mole cular data recapture the correct phylogeny better than do morphologica l data, and the commonly used analytical methods are all equally robus t in producing this phylogeny.