Evolution

Same But Different

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Science  21 Jan 2011:
Vol. 331, Issue 6015, pp. 264
DOI: 10.1126/science.331.6015.264-a
CREDIT: SIMONE DESROCHES

Adaptation to local environments accompanied by reproductive isolation can result in ecological speciation among populations. One example of such adaptation is the color variation seen in several reptile species found in the gypsum sands of White Sands, New Mexico. Animals living within the white or dark sand environments are light- or dark-colored, respectively. By simultaneously comparing multiple genetic and phenotypic traits, Rosenblum and Harmon tested whether this divergence has led to ecological speciation in three replicate lizard species that display this pattern (Aspidoscelis inornata, Sceloperus undulatus, and Holbrookia maculata). They detected signals of ecological speciation in all three species, including the clear divergence in color phenotype, but also in body shape and size. The degree to which speciation has progressed (as evidenced by genetic divergence), however, varied substantially. Phenotypical adaptations to local environmental variation were observed in all species, but thus far, only H. maculata showed evidence of true ecological speciation. Overall, these results provide insight into the variety of ways species can respond to apparently similar selective regimes.

Evolution 10.1111/j.1558-5646.2010.01190.x (2010).

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