ELECTROPHORETIC VARIATION AND DIFFERENTIATION IN FOUR STRAINS OF DOMESTICATED RAINBOW TROUT (SALMO GAIRDNERI)

Abstract
A total of 1462 rainbow trout (S. gairdneri Richardson) representing 4 California [USA] domestic strains, were examined electrophoretically at 24 gene loci to investigate the amount of genetic variability within strains and genetic differentiation between strains, relative to wild populations. Estimated heterozygosites of 0.071-0.134 were similar to those reported for wild populations and indicated that the domestic strains were at least as variable as wild population. Genetic distances between strains ranged from 0.011-0.067, values typical of the level of differentiation observed between local conspecific populations in a variety of organisms. This high level of heterozygosity maybe due to mixing of populations in the strains'' histories and perhaps also due to balancing selection.