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Genetic structure and relationships among populations of Hyalella azteca and H. montezuma (Crustacea:Amphipoda)
Yihao Duan, Sheldon I. Guttman, James T. Oris and A. John Bailer
Journal of the North American Benthological Society
Vol. 19, No. 2 (June 2000), pp. 308-320
Stable URL: http://www.jstor.org/stable/1468073
Page Count: 13
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AbstractAllozyme analysis was used to examine the genetic structure of 12 Hyalella azteca populations collected from geographically isolated sites in the United States and Canada. Hyalella montezuma also was analyzed electrophoretically to determine genetic differentiation between recognized congeners. Extensive qualitative and quantitative genetic differentiation was observed across the 9 electrophoretically identified groups, which were all presumed to be H. azteca. Levels of genetic differentiation between all pairs of H. azteca groups were higher than when any one of them was compared to H. montezuma (Nei’s genetic distance, D = 0.27–2.27). These groups were considered distinct species because of large genetic differences, probable lack of gene flow, comparatively larger allozyme differences than observed between H. azteca and H. montezuma, prominent local differentiation, and extremely low genetic variability. Genotype frequencies in all populations markedly deviated from Hardy–Weinberg equilibrium with a deficiency of heterozygotes. Hyalella populations were strongly subdivided even within a local region. No positive trend was observed between genetic and geographic distance. A thorough molecular systematic analysis of populations throughout the range of H. azteca is essential to identify the actual number of species included in this taxon.
Journal of the North American Benthological Society © 2000 The University of Chicago Press