Genetic diversity and population structure of the threatened Bliss Rapids snail (Taylorconcha serpenticola)

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The authors assessed allelic variation of 11 microsatellite loci within and among 29 samples (820 specimens) of the Bliss Rapids snail (Taylorconcha serpenticola) from the Snake River basin in south-central Idaho. The goals were to assess genetic structure and test whether habitat fragmentation resulting from construction of three hydroelectric dams along the Snake River has impacted population connectivity of this federally listed yet poorly known species. Mean allelic richness and expected heterozygosity across all loci ranged from 2.0–4.4 and 0.317–0.716, respectively. The average FST [ST should be subscripted] over loci was moderate (0.15133, P<0.05) and 308 and 406 pairwise comparison were significant (Bonferroni corrected P<0.000123), demonstrating extensive population subdivision in general. An AMOVA revealed substantial variation among samples from six spring-fed tributary systems (12.48%, P<0.05), whereas significant genetic differences were not detected between tributaries and the main stem river or among drainage reaches segmented by dams. The authors did not find a consistent geographic or habitat-related pattern of genetic variation or a significant isolation by distance trend. They attribute the weak genetic structuring of riverine populations in the Hagerman and Bliss reaches to passive dispersal within the water column, which may enable occasional passage through dams. The stronger genetic structuring observed in the Shoshone reach may be due to mixing of main stem and (strongly differentiated) tributary populations in this portion of the river, which receives a large discharge from many springs.

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ELECTRONIC FILE - Zoology

NOTE: This manuscript or a revision was published in June 2009 in the journal Freshwater Biology (vol. 54, issue 6; pages 1285-1299). Should try to obtain that article if this work is to be used/cited.