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Heritable variation in garter snake color patterns in postglacial populations
Michael F Westphal1, Jodi L Massie, Joanna M Bronkema
1Division of Biology and The Ecological Genomics Institute, Kansas State University, Manhattan, Kansas, United States of America. mwestpha@blm.gov
Plos One
|September 22, 2011
Summary
Climate change may alter species ranges, impacting genetic diversity. Contrary to expectations, postglacial garter snake populations showed equal or higher genetic variation for pigmentation than southern refuge populations.
Area of Science:
- Evolutionary Biology
- Climate Change Ecology
- Population Genetics
Background:
- Global climate change is predicted to cause northward range shifts in plant and animal populations.
- Understanding genetic diversity patterns in post-Ice Age populations is key to predicting climate change impacts.
- Rapid expansion into new landscapes may decrease genetic diversity, potentially hindering adaptation.
Purpose of the Study:
- To investigate genetic diversity and heritability of pigmentation traits in common garter snakes (Thamnophis sirtalis) across a north-south gradient.
- To compare genetic variation in a postglacial population versus a southern refuge population.
- To assess the impact of past glacial cycles on current genetic diversity and adaptability.
Main Methods:
- Conducted two quantitative genetic studies using full-sib designs in Manitoba (N=144) and South Dakota (N=653).
- Performed a smaller phenotypic analysis in Kansas (N=44).
- Compared mean levels of pigmentation, genetic variation, and heritability for three pigmentation traits.
Main Results:
- Found that genetic variance for pigmentation traits was the same or higher in the postglacial population compared to the southern population.
- Heritability for the studied pigmentation traits was also equal or greater in the postglacial population.
- Results contradicted the expectation of decreased genetic diversity in postglacial populations.
Conclusions:
- Postglacial expansion may not necessarily lead to reduced genetic diversity or heritability.
- Common garter snake populations in postglacial areas retain significant genetic variation for adaptive traits.
- Findings suggest resilience in postglacial populations regarding adaptation to environmental changes.
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