Authors
S.
R. Narum
C. Contor
A. Talbot
M. S. Powell
Report Reference
Publication Date
30 April
2004
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Genetic
divergence of sympatric resident and anadromous forms of Oncorhynchus
mykiss in the Walla Walla River, U.S.A.
Abstract |
| Genetic
structure (six microsatellites) and gene flow were examined among
anadromous (steelhead; n=326), resident (rainbow trout; n=52),
and mixed (n=407) Oncorhynchus mykiss life-history
forms collected from the major drainages the mainstem Walla Walla
River and the Touchet River within the Walla Walla River sub-basin,
Washington, U.S.A. Genetic structure was detected between the two
major drainages. Exact tests, FST, multi-locus assignment
tests and a neighbour-joining dendrogram revealed genetic divergence
between sympatric reference populations of adult steelhead and resident
rainbow trout in the mainstem Walla Walla River, but not in the Touchet
River. Tests of Hardy-Weinberg equilibrium indicated anadromous and
resident O. mykiss reference populations were in equilibrium,
but many of the mixed life-history collections were out of equilibrium.
Populations out of equilibrium in the mainstem Walla Walla River appeared
to be admixtures as confirmed by multi-locus assignment tests. This
is evidence of genetic divergence probably resulting from assortative
mating between life-history forms or out-of-basin stocking practices. |
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