Chromosomal, Electrophoretic, and Breeding Studies of Selected Populations of Deer Mice ( Peromyscus Maniculatus ) and Black‐eared Mice ( P. Melanotis )

The deer mouse, Peromyscus maniculatus, has the widest geographic distribution of the native of rodents in North America. This is correlated with a high degree of genetic diversity as reflected by (1) the amount of morphological divergence and the large number of subspecies (Hall and Kelson, 1959; King, 1968), (2) the unusual amount of geographic chromosomal polymorphism (Arakaki and Sparkes, 1967; Duffey, 1972; Kreizinger and Shaw, 1970; Ohno et al., 1966; Singh and McMillan, 1966; Sparkes and Arakaki, 1966; Bradshaw and George, 1969) and (3) the degree of biochemical variation (Rasmussen, 1964, 1968, and 1970; Rasmussen and Koehn, 1966; Rasmussen et al., 1968; Brown and Welser, 1968; and Jensen and Rasmussen, 1971). The complexity of this is further compounded because there are several peripheral populations, subspecies and closely related species which are distinguishable from typical P. maniculatus by varying degrees of morphological divergence (Blair, 1950). Although this situation poses a nightmare to the taxonomist, an analysis of genetic relationship of such populations provides a valuable approach to the study of mammalian evolution. Rasmussen (1970) has already reported on one such study involving the degree of genetic diversity as reflected by electrophoretic patterns. He chose certain populations of deer mice