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Genetic Structure and Gene Flow in Chinook Salmon Populations of California
Author(s) -
Bartley Devin M.,
Gall G. A. E.
Publication year - 1990
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1990)119<0055:gsagfi>2.3.co;2
Subject(s) - gene flow , biology , chinook wind , oncorhynchus , genetic variation , genetic diversity , genetic structure , population , pleistocene , ecology , glacial period , genetic variability , population genetics , genetic distance , zoology , fishery , genetics , gene , demography , paleontology , sociology , fish <actinopterygii> , genotype
We analyzed genetic variation in 35 populations of Chinook salmon Oncorhynchus tshawytscha from northern California by use of allozymes detected by horizontal starch gel electrophoresis. Products of 53 loci from 27 enzyme systems were used to characterize the genetic structure, assess hierarchical relationships, and estimate levels ofgene flow among the populations. Average heterozygosity, 0.038, and percent polymorphic loci, 41 %, found in California populations were similar to previously reported values from more northern locations. Ten hatchery populations were included in the analysis and generally possessed levels ofgenetic variability similar to nearby wild populations. Although estimated average gene flow was 1.16, high from an evolutionary standpoint, and genetic identities were greater than 0.990, we observed genetic differentiation among populations. Distribution of specific alleles, cluster analysis based on genetic identity estimates, and gene diversity analyses indicated that inland populations ofCalifornia Chinook salmon were genetically differentiated by drainage and river system. Coastal populations did not cluster geographically. We suggest that founder effects and population bottlenecks after frequent volcanic activity are mechanisms leading to different levels ofgenetic variability within California. Whereas extensive glaciation during the Pleistocene displaced many salmon populations in Washington and Canada, glacial activity in California was restricted to higher elevations. Therefore, drainage patterns and Chinook salmon populations remained intact during this period. We propose that these differences in the distribution and extent of glacial activity in North America during the Pleistocene may account for more subpopulation structure in California than in more northern areas.