![]() ![]() ![]() Gov't, P.H.S.England4 09:00Heredity (Edinb). Hoekstra, H EKrenz, J GNachman, M WengComparative StudyResearch Support, U.S. All mutations are not bad because the changes can allow for future survival of the species. Individuals change color to blend in with the environment C. In your answer, explain how the dark coat-color mutation can be an advantage to some mice and a disadvantage to others. The rock pocket mice have a mutation in a gene that leads to the dark fur color. Together, the results suggest that color variation can evolve very rapidly over small geographic scales and that gene flow can both hinder and promote local adaptation. Use the example of rock pocket mice to explain why this statement is not true. Finally, we raise the possibility that, in some cases, migration between populations of pocket mice inhabiting different lava flows may be responsible for similar melanic phenotypes in different populations. At a finer geographical scale, high levels of gene flow between neighboring melanic and light populations suggest the selection acting on color must be quite strong to maintain habitat-specific phenotypic distributions. Using Mantel tests, we show that there is no correlation between color variation and mtDNA phylogeny, suggesting that pelage coloration has evolved rapidly. Analyses of mtDNA sequences from these same individuals revealed strong population structure in this species across its range, where most variation (63%) was partitioned between five geographic regions. Most of these mice have a sandy, light-colored coat that enables them to blend in with the light-colored desert rocks and sand on which they live. First, we quantified variation in pelage color (n=107 mice) and habitat color (n=51 rocks) using a spectrophotometer, and showed that there was a correlation between pelage color and habitat color across 14 sampled populations (R2=0.43). The rock pocket mouse, Chaetodipus intermedius, a small, nocturnal animal, is found in the deserts of the southwestern United States. On the other hand, dark-colored rock pocket mouse populations have been found living on black, basaltic rock formations caused by geologic lava flows. ![]() Rock pocket mice, however, have had an enormous impact on science. Here, we investigate whether phenotypic variation in color is correlated with local environmental conditions or with phylogenetic history. Most rock pocket mouse populations have sandy-colored fur, which is consistent with the light color of the desert rocks and sand on which they live. And at just 15 grams, this tiny mouse weighs about as much as a handful of paper clips. Rock pocket mice, Chaeotdipus intermedius, are an ideal system in which to study intraspecific phenotypic divergence because of the extensive color variation observed within this species. Elucidating the causes of population divergence is a central goal of evolutionary biology. ![]()
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