Adaptive basis of geographic variation: Genetic, phenotypic and environmental differences among beach mouse populations

Citation:

Mullen LM, Vignieri SN, Gore JA, Hoekstra HE. Adaptive basis of geographic variation: Genetic, phenotypic and environmental differences among beach mouse populations. Proceedings of the Royal Society B: Biological Sciences 2009;276:3809-18.
PDF418 KB

Date Published:

Nov 7

Abstract:

A major goal in evolutionary biology is to understand how and why populations differentiate, both genetically and phenotypically, as they invade a novel habitat. A classical example of adaptation is the pale colour of beach mice, relative to their dark mainland ancestors, which colonized the isolated sandy dunes and barrier islands on Florida's Gulf Coast. However, much less is known about differentiation among the Gulf Coast beach mice, which comprise five subspecies linearly arrayed on Florida's shoreline. Here, we test the role of selection in maintaining variation among these beach mouse subspecies at multiple levels-phenotype, genotype and the environments they inhabit. While all beach subspecies have light pelage, they differ significantly in colour pattern. These subspecies are also genetically distinct: pair-wise F(st)-values range from 0.23 to 0.63 and levels of gene flow are low. However, we did not find a correlation between phenotypic and genetic distance. Instead, we find a significant association between the average 'lightness' of each subspecies and the brightness of the substrate it inhabits: the two most genetically divergent subspecies occupy the most similar habitats and have converged on phenotype, whereas the most genetically similar subspecies occupy the most different environments and have divergent phenotypes. Moreover, allelic variation at the pigmentation gene, Mc1r, is statistically correlated with these colour differences but not with variation at other genetic loci. Together, these results suggest that natural selection for camouflage-via changes in Mc1r allele frequency-contributes to pigment differentiation among beach mouse subspecies.

Notes:

Mullen, Lynne MVignieri, Sacha NGore, Jeffery AHoekstra, Hopi EengResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.England2009/08/07 09:00Proc Biol Sci. 2009 Nov 7;276(1674):3809-18. doi: 10.1098/rspb.2009.1146. Epub 2009 Aug 5.

Last updated on 10/21/2016