TitleAdaptive divergence within and between ecotypes of the terrestrial garter snake, Thamnophis elegans, assessed with F-ST-Q(ST) comparisons
Publication TypeJournal Article
Year of Publication2007
AuthorsManier, MK, Seyler, CM, Arnold, SJ
JournalJournal of Evolutionary Biology
Keywordscolouration diversifying selection ecotypic variation F-SC heritability microsatellites Q(SC) Q-statistics scalation color-pattern variation erie water snakes natural-selection lake-erie gene flow quantitative traits g-matrix behavioral variation multiple

Populations of the terrestrial garter snake (Thamnophis elegans) around Eagle Lake in California exhibit dramatic ecotypic differentiation in life history, colouration and morphology across distances as small as a few kilometres. We assayed the role of selection in ecotypic differentiation in T. elegans using F-ST-Q(ST) analysis and identified selective agents using direct and indirect observations. We extended the conventional implementation of the F-ST-Q(ST) approach by using three-level analyses of genetic and phenotypic variance to assess the role of selection in differentiating populations both within and between ecotypes. These results suggest that selection has driven differentiation between as well as within ecotypes, and in the presence of moderate to high gene flow. Our findings are discussed in the context of previous correlational selection analyses which revealed stabilizing and correlational selection for some of the traits examined.