Genic Variation in Hybridizing Populations of Gophers (Genus Thomomys)

Allelic variation at 27 structural gene loci was studied electrophoretically in five populations of Thomomys bottae and one of T. umbrinus in Arizona. The status of eight individuals identified karyotypically as F1 hybrids was confirmed by analysis of their genotypes at several marker loci. Lack of genie introgression between populations of the two species, despite hybridization in a zone of contact in the Patagonia Mountains, presumably results from hybrid sterility caused by genie and/or chromosomal imbalance. Levels of genie heterozygosity (H) are moderate to high in both species (T. bottae, H = .071 [.043−.106]; T. umbrinus, H=.O31). Genie similarity among populations of T. bottae is also high (S = .933 [.90–96]), suggesting either effective gene flow or strong, uniform selection in the populations sampled.