Linkage and Selection Analysis of Biochemical Variants in Peromyscus maniculatus

During 1976 deermice ( Peromyscus maniculatus ) were sampled from 12 populations along the front range of the Rocky Mountains in eastern Colorado. Tissue samples for field-captured males, nonpregnant females, pregnant females, and field -conceived, laboratory-reared offspring were analyzed for 19 protein systems (loci) using starch-gel electrophoresis. Nine loci (ADH, ALB, EST-4, GOT-1, IDH, PEPT-1, 6-PGD, SDH, TRF) provided adequate polymorphism for linkage study; five were used for selection analysis. Lod-score analyses for linkage determinations were generated by pairwise loci comparisons over recombination levels of 0 to 50%. Most pairings reflected evidence for nonlinkage. Maximum evidence for linkage, not statistically significant (P > 0.05), was between the ADH and 6-PGD loci at 30% recombination. If a significant trend was found through further testing, this linkage relationship would be one of weak segregational integrity, either syntenic or interchromosomal. Other pairings that showed some evidence of linkage were ADH-GOT-1, ADH-IDH, ALB-PEPT-1, ALB-SDH, and EST-4-SDH. Four of five loci tested showed significant gene frequency changes using the Christiansen and Frydenberg (1973) method of selection analysis. Seventy-one percent of the changes occurred during prezygotic selection analysis. However, significant changes due to selection were shown over different life-history components in different populations, possibly suggesting strong populational subdivision along the altitudinal cline.