DNA AND ALLOZYME MARKERS PROVIDE CONCORDANT ESTIMATES OF POPULATION DIFFERENTIATION - ANALYSES OF US AND CANADIAN POPULATIONS OF YUKON RIVER FALL-RUN CHUM SALMON (ONCORHYNCHUS-KETA)

Although the number of genetic markers available for fisheries researc h has steadily increased in recent years, there is limited information on their relative utility. In this study, we compared the preformance of different ''classes'' of genetic markers (mitochondrial DNA (mtDNA ), nuclear DNA (nDNA), and allozymes) in terms of estimating levels an d partitioning of genetic variation and of the relative accuracy and p recision in estimating population allocations to mixed-stock fisheries . Individuals from eight populations of fall-run chum salmon (Oncorhyn chus keta) from the Yukon River in Alaska and Canada were assayed at 2 5 loci. Significant differences in mitochondrial haplotype and nuclear allele Frequencies were observed among five drainages. Populations fr om the U.S.-Canada border region were not clearly distinguishable base d on multilocus allele frequencies. Although estimates of total geneti c diversities were higher for the DNA loci (H-t = 0.592 and h = 0.647 for nDNA and mtDNA, respectively) compared with protein allozymes (H-t = 0.250), estimates of the extent of population differentiation were highly concordant across marker classes (mean theta = 0.010, 0.011, an d 0.016 for allozymes, nDNA, and mtDNA, respectively). Simulations of mixed-stock fisheries composed of varying contributions of U.S. and Ca nadian populations revealed a consistent bias for overallocation of Ca nadian stocks when expected Canadian contributions varied from 0 to 40 %, due primarily to misallocations among genetically similar border po pulations. No single marker class is superior for differentiating popu lations of this species at the spatial scale examined.