Genic Variation in the Peromyscus truei Group (Rodentia: Cricetidae)

Genic analyses of cytotypes of Peromyscus truei and P. difficilis were conducted to determine the magnitude of genic evolution that has accompanied chromosomal divergence. Two species currently assigned to the boylii group were included. The distinctness of northern and southern cytotypes of P. truei was documented and supports other investigators who concluded that the southern cytotype should be elevated to specific status. Cytotypes of P. difficilis were not genically distinct at 28 presumptive loci and do not appear to represent separate species. P. attwateri, currently placed in the boylii group, is related closely to P. difficilis. P. diffidlis is the sister taxon of P. gratus.