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Divergence along a steep ecological gradient in lake whitefish (Coregonus sp.)
P Vonlanthen1, D Roy, A G Hudson
1Division of Aquatic Ecology & Evolution, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland. pascal.vonlanthen@eawag.ch
Journal of Evolutionary Biology
|January 28, 2009
Summary
Investigating whitefish in a Swiss lake revealed genetic and morphological patterns along depth gradients. Divergent selection drives adaptive divergence, but the long-term stability of this pattern remains uncertain.
Area of Science:
- Evolutionary biology
- Ecology
- Genetics
Background:
- Understanding diversity in young adaptive radiations requires quantitative data on genetic and phenotypic variation.
- Whitefish (Coregonus spp.) in Swiss lakes represent a model system for studying adaptive radiation.
Purpose of the Study:
- To investigate the genetic and phenotypic diversity of whitefish in Lake Neuchâtel along an ecological depth gradient.
- To determine the role of divergent natural selection and gene flow in shaping whitefish diversity.
Main Methods:
- Continuous sampling of whitefish populations across spawning habitats in time and space.
- Analysis of genetic differentiation (FST) and trait-specific differentiation (PST) along an ecological depth gradient.
- Morphological and genetic analyses of sampled whitefish populations.
Main Results:
- A clear cline-like pattern in whitefish genetics and morphology was observed along the depth gradient in Lake Neuchâtel.
- Trait-specific PST values significantly higher than FST values indicate divergent natural selection.
- Evidence suggests adaptive divergence along the depth gradient persists despite gene flow.
Conclusions:
- Divergent natural selection is a key mechanism structuring whitefish diversity along an ecological depth gradient.
- The observed pattern may represent a stable selection-gene flow balance, incipient speciation, or reverse speciation due to anthropogenic impacts.
- Further research is needed to clarify the long-term evolutionary trajectory of whitefish populations in Lake Neuchâtel.
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