MBE Advance Access originally published online on October 1, 2008
Molecular Biology and Evolution 2009 26(1):35-45; doi:10.1093/molbev/msn218
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Research Articles |
The Genetic Basis of Phenotypic Convergence in Beach Mice: Similar Pigment Patterns but Different Genes
,
,1
* Division of Biological Sciences, University of California, San Diego
Institute of Biochemistry Medical Faculty, University of Leipzig, Leipzig, Germany
Department of Organismic and Evolutionary Biology and The Museum of Comparative Zoology, Harvard University, Cambridge, MA
E-mail: hoekstra{at}oeb.harvard.edu.
Accepted for publication September 19, 2008.
Convergent evolution is a widespread phenomenon seen in diverse organisms inhabiting similar selective environments. However, it is unclear if similar phenotypes are produced by the same or different genes and mutations. Here we analyze the molecular mechanisms underlying convergent pigment pattern among subspecies of the beach mouse (Peromyscus polionotus) inhabiting the Gulf and Atlantic coasts of Florida. In these two geographic regions, separated by more than 300 km, "beach mice" have lighter colored coats than do their mainland counterparts, produced by natural selection for camouflage against the pale coastal sand dunes. We measured color pattern in eight beach mouse subspecies and showed that three of the Gulf Coast subspecies are more phenotypically similar to an Atlantic coast subspecies than to their Gulf Coast neighbors. However, light-colored beach mice do not form a monophyletic group. Previous results implicated a single derived amino acid change in the melanocortin-1 receptor (Mc1r) as a major contributor to pigment pattern in the Gulf Coast beach mice; despite phenotypic similarities, the derived Mc1r allele was not found in the Atlantic coast beach mouse populations. Here we show that Atlantic coast beach mice have high levels of Mc1r polymorphism but they lack unique alleles. Functional assays revealed that single amino acid mutations segregating in Atlantic coast beach mice do not cause any change in Mc1r activity compared with the activity of Mc1r from dark-colored mice. These joint results show that convergent pigment patterns in recently diverged beach mouse subspecies—whose developmental constraints are presumably similar—have evolved through a diversity of genetic mechanisms.
Key Words: adaptation • color • melanocortin-1 receptor • parallel evolution • Peromyscus polionotus • phenotypic evolution
1 Present address: Rudolf-Boehm-Institute of Pharmacology and Toxicology, Medical Faculty, University of Leipzig, D-04107 Leipzig, Germany.
Patricia Beldade, Associate Editor
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  L. M. Mullen, S. N. Vignieri, J. A. Gore, and H. E. Hoekstra Adaptive basis of geographic variation: genetic, phenotypic and environmental differences among beach mouse populations Proc R Soc B, November 7, 2009; 276(1674): 3809 - 3818. [Abstract] [Full Text] [PDF]
|
|