Genetics, hindsight, and recovery of Mohave tui chub From Program for San Luis Obispo...
Parmenter, Steve1, Chen, Yongjiu2, Bernie May2
1 California Department of Fish and Game, 407 West Line Street, Bishop, CA 93514, Spar@dfg.ca.gov
2 Genomic Variation Laboratory, Department of Animal Science, the University of California, Davis, CA 95616
Mohave tui chub (Siphateles bicolor mohavensis [Snyder]) is the only fish native to the Mojave [sic] River, California. Mass intergeneric hybridization with introduced arroyo chub (Gila orcutti [Eigenmann and Eigenmann]) displaced tui chubs from the Mojave River in the 1930s. Mohave tui chubs persisted in one relictual population, Mohave Chub Spring (MC Spring), from which three refuge populations derive. Employing 12 microsatellite DNA loci, our study characterized genetic diversity of each Mohave tui chub population, compared them with other tui chub taxa, and examined the taxonomic status of the common cyprinid fish in the Mojave River today. Mohave tui chubs are genetically differentiated from other tui chubs in the southern Great Basin. We found only unhybridized Arroyo chubs in the Mojave River, and unhybridized Mohave tui chubs in the refugial populations. Population substructure is evident among the four Mohave tui chub populations. Contrary to our expectation, the source population at MC Spring has significantly less genetic diversity than populations historically derived from it. Our findings suggest that a small genetically effective population size in MC Spring has reduced diversity through genetic drift in the five decades since the original transplant was made. A one-time bottleneck of 10 individuals during the founding of the Camp Cady population is evident in both reduced genetic diversity, and divergence of that population from all others. Two additional refuges, Lake Tuendae and China Lake, possess significantly higher levels of diversity. We recommend instituting artificial gene flow to rebuild genetic diversity in MC Spring and Camp Cady, and to better conserve allelic diversity in the species as a whole. New populations established in the future should be derived from Lake Tuendae and China Lake.
Parmenter, Steve1, Chen, Yongjiu2, Bernie May2
1 California Department of Fish and Game, 407 West Line Street, Bishop, CA 93514, Spar@dfg.ca.gov
2 Genomic Variation Laboratory, Department of Animal Science, the University of California, Davis, CA 95616
Mohave tui chub (Siphateles bicolor mohavensis [Snyder]) is the only fish native to the Mojave [sic] River, California. Mass intergeneric hybridization with introduced arroyo chub (Gila orcutti [Eigenmann and Eigenmann]) displaced tui chubs from the Mojave River in the 1930s. Mohave tui chubs persisted in one relictual population, Mohave Chub Spring (MC Spring), from which three refuge populations derive. Employing 12 microsatellite DNA loci, our study characterized genetic diversity of each Mohave tui chub population, compared them with other tui chub taxa, and examined the taxonomic status of the common cyprinid fish in the Mojave River today. Mohave tui chubs are genetically differentiated from other tui chubs in the southern Great Basin. We found only unhybridized Arroyo chubs in the Mojave River, and unhybridized Mohave tui chubs in the refugial populations. Population substructure is evident among the four Mohave tui chub populations. Contrary to our expectation, the source population at MC Spring has significantly less genetic diversity than populations historically derived from it. Our findings suggest that a small genetically effective population size in MC Spring has reduced diversity through genetic drift in the five decades since the original transplant was made. A one-time bottleneck of 10 individuals during the founding of the Camp Cady population is evident in both reduced genetic diversity, and divergence of that population from all others. Two additional refuges, Lake Tuendae and China Lake, possess significantly higher levels of diversity. We recommend instituting artificial gene flow to rebuild genetic diversity in MC Spring and Camp Cady, and to better conserve allelic diversity in the species as a whole. New populations established in the future should be derived from Lake Tuendae and China Lake.
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