Genetic analyses of Central Valley trout populations

摘要: Genetic variation found at 11 microsatellite loci was used to describe population structure for steelhead and rainbow trout (Oncorhynchus mykiss) in the Central Valley, California, looking at both spatial and temporal genetic variation as well as relationships among hatchery and wild populations. We analyzed genetic diversity at two scales: within drainage spatial allelic diversity analyzed for five trout populations sampled in Clear Creek; between and among drainage genetic diversity analyzed for 23 population of trout found in the Central Valley. DNA was amplified and analyzed for 1570 trout samples. Significant regional spatial structuring of populations was apparent, both within Clear Creek and among trout populations in the Central Valley. Significant differences in allelic frequencies were found among most river or drainage systems containing wild trout. However, less than 1% of the molecular variance could be attributed to differences between trout populations found within the Sacramento River and samples from the San Joaquin River drainage. Hatchery populations were shown to be similar in genetic diversity to geographically proximate local wild populations. Overall classification accuracy of single individuals to their stream of origin using these 11 microsatellite loci was 83%. Garza and Williamson’s (2001) M over all populations of trout in the Central Valley was M= 0.626, below the published threshold (M< 0.68), supporting recent population reductions for steelhead within the Central Valley. Average estimated effective population size for Central Valley steelhead populations, however, was relatively high (Ne= 5066). Significant allelic …