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Long-term effective population sizes, temporal stability of genetic composition and potential for local adaptation in anadromous brown trout (Salmo trutta ) populations.
- Source :
- Molecular Ecology; Dec2002, Vol. 11 Issue 12, p2523-2535, 13p
- Publication Year :
- 2002
-
Abstract
- Abstract We examined the long-term temporal (1910s to 1990s) genetic variation at eight microsatellite DNA loci in brown trout (Salmo trutta L) collected from five anadromous populations in Denmark to assess the long-term stability of genetic composition and to estimate effective population sizes (N <subscript> e </subscript> ). Contemporary and historical samples consisted of tissue and archived scales, respectively. Pairwise θ<subscript>ST</subscript> estimates, a hierarchical analysis of molecular variance (amova) and multidimensional scaling analysis of pairwise genetic distances between samples revealed much closer genetic relationships among temporal samples from the same populations than among samples from different populations. Estimates of N <subscript> e </subscript> , using a likelihood-based implementation of the temporal method, revealed N <subscript> e </subscript> ≥ 500 in two of three populations for which we have historical data. A third population in a small (3 km) river showed N <subscript> e </subscript> ≥ 300. Assuming a stepping-stone model of gene flow we considered the relative roles of gene flow, random genetic drift and selection to assess the possibilities for local adaptation. The requirements for local adaptation were fulfilled, but only adaptations resulting from strong selection were expected to occur at the level of individual populations. Adaptations resulting from weak selection were more likely to occur on a regional basis, i.e. encompassing several populations. N <subscript> e </subscript> appears to have declined recently in at least one of the studied populations, and the documented recent declines of many other anadromous brown trout populations may affect the persistence of local adaptation. [ABSTRACT FROM AUTHOR]
- Subjects :
- BROWN trout
MICROSATELLITE repeats
ANIMAL populations
ANIMAL genetics
Subjects
Details
- Language :
- English
- ISSN :
- 09621083
- Volume :
- 11
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- Molecular Ecology
- Publication Type :
- Academic Journal
- Accession number :
- 8563562
- Full Text :
- https://doi.org/10.1046/j.1365-294X.2002.01634.x