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A single amino acid mutation contributes to adaptive beach mouse color pattern
Hopi E Hoekstra1, Rachel J Hirschmann, Richard A Bundey
1Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA. hoekstra@ucsd.edu
Science (New York, N.Y.)
|July 11, 2006
Summary
A single gene mutation in melanocortin-1 receptor (Mc1r) explains significant color variation in wild beach mice populations. This finding links molecular changes to adaptive evolution in natural settings.
Area of Science:
- Evolutionary biology
- Genetics
- Animal coloration
Background:
- Beach mice display distinct color patterns compared to mainland relatives, driven by natural selection for camouflage (crypsis).
- The melanocortin-1 receptor (Mc1r) is a key gene involved in pigmentation.
- Convergent evolution of similar light coloration in beach mice populations on different coasts raises questions about underlying genetic mechanisms.
Purpose of the Study:
- To identify the genetic basis for the adaptive color variation in beach mice.
- To investigate the role of the melanocortin-1 receptor (Mc1r) gene in beach mouse pigmentation.
- To explore the molecular mechanisms behind convergent evolution of coloration in isolated populations.
Main Methods:
- Genetic crosses were performed to analyze the inheritance of pigmentation traits.
- Allelic variation in the Mc1r gene was quantified and correlated with phenotypic variation.
- Geographic distribution of Mc1r alleles was assessed in different beach mouse populations.
Main Results:
- A derived, charge-changing amino acid mutation in Mc1r was identified in beach mice, reducing receptor function.
- Mc1r allelic variation accounted for 9.8% to 36.4% of the variation in seven pigmentation traits.
- The derived Mc1r allele was found in Gulf Coast beach mice but absent in Atlantic coast mice with similar light coloration.
Conclusions:
- A single coding mutation in Mc1r is linked to adaptive quantitative variation in wild beach mouse populations.
- Different molecular mechanisms may underlie the convergent evolution of light coloration in geographically separated beach mouse populations.
- This study provides a direct link between a specific gene mutation and adaptive phenotypic evolution in a natural environment.
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