“…Whereas studies by several investigators (Avise et al, 1974a,b;Bowers et al, 1973;Garten, 1976;Jensen, 1970;Jensen and Rasmussen, 1971;Johnson and Packard, 1974;Selander et al, 1971;Smith et al, 1973) have increased our understanding of the genetics of various other species of Peromyscus, quantification of the amount of genomic modification accompanying speciation has not been thoroughly examined. Data now available from our studies permit us to assess the genetics of speciation at five levels of differentiation among six of the seven species groups of the subgenus Peromyscus.…”