| old mice, young islands and competing biogeographical hypotheses. | naturally occurring variation within a small rodent species native to the southeastern usa, peromyscus polionotus, has interested biologists for nearly a century. this species has contributed significantly to our understanding of geographical variation and has often been presented as an example of adaptive evolution. much of the interest in this organism has been predicated on assumptions that the species is relatively young (<300 000 bp) and that coastal populations have a very recent history ( ... | 2007 | 17956552 |
| natural selection along an environmental gradient: a classic cline in mouse pigmentation. | we revisited a classic study of morphological variation in the oldfield mouse (peromyscus polionotus) to estimate the strength of selection acting on pigmentation patterns and to identify the underlying genes. we measured 215 specimens collected by francis sumner in the 1920s from eight populations across a 155-km, environmentally variable transect from the white sands of florida's gulf coast to the dark, loamy soil of southeastern alabama. like sumner, we found significant variation among popul ... | 2008 | 18489719 |