Assessment Of Genetic Diversity Of Pacific Lamprey

This study is the first to document genetic differences among Pacific lamprey across their range by AFLP and SSR molecular marker techniques. The assays will be useful tools for measuring the population genetic structure and fisheries resources in Pacific lamprey. We examined collections of migrating adult Pacific lamprey from Naka River, Japan; Moose River, Alaska; and six locations in the Pacific Northeast: the Toutle River, Willamette River, Deschutes River, John Day River Dam, Rogue River, and Klamath River.This study is based on variation at 180 (32.4%) polymorphic loci of 556 AFLP loci generated by seven primer combinations. The percentage of polymorphic bands for each pair of primer combinations ranged from 12.7-40.5%.On average, 79.4 polymorphic bands are amplified by one primer combination. SSR analysis of 210 individuals using 5 primer combinations showed 17 alleles,the effected alleles number of each loci were 3.4, observed polymorphism information content (PIC) range from 0.291 to 0.763. Significant differences existed in heterozygosity, ranging from 0.429 to 0.565 across populations for SSR and from 0.066 to 0.111 for AFLP. The result of SSR analysis were higher than that of AFLP technique. The AMOVA testing for differences across three geographical regions (the Pacific Northeast, Alaska, and Japan), produced the largest partitioning of genetic variation within populations, but only showed 10.6% among populations. Likewise, all pairwise FST comparisons between the collections showed no significant differences. Analysis of the data using STRUCTURE to assign genotypes to lineages suggested six hypothetical aggregations, the percentage of the eight populations in six hypothetical aggregations is different, it showed obvious hybridization and gene infiltration among populations.Similar patterns were evident in the cluster analysis of all 218 genotypes by AFLP and SSR molecular marker techniques. The most divergent cluster was comprised of populations from the Naka River, Japan, and Moose River, Alaska, these populations showed significant differences among lamprey from the other Pacific Northeast populations. A second divergent cluster was formed by WR and NFT. Similarly, the cluster of RR, KLA and JD collections were significant. Our results indicated a simple pattern did not discribe the population genetic structure of Pacific lamprey. Our results call attention to the need for better data and analyses of the demographic status, genetic variation, and migratory behavior of Pacific lamprey.