Evolution of Novel Color Phenotypes During Population Establishment: Genetic, Biochemical, and Ecological Considerations
AuthorFarrar, Victoria Sophia
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractWhen do novel adaptations arise as rearrangements of ancestral components and when do they arise de novo? Answering this question requires direct study of the proximate mechanisms behind novel phenotypes that arise from diverse starting points along different historical contingencies. Here we capitalize on uniquely replicated historical sequences of population establishment in the house finch (Haemorphous mexicanus) to study the evolution of color-producing enzymatic pathways that underlie population divergence in color phenotypes. We first evaluated genetic diversity and differentiation in a neutral marker (the mitochondrial NADH II dehydrogenase gene) across 12 study populations, both in the ancestral range in Arizona and across the Continental Divide in Montana at the range edge. We uncovered 29 haplotypes in our samples, describing 17 new haplotypes for this species. We then examined the influence of inter-population differences (such as habitat, age, and genetic relationships) on variation in the network of enzymatic reactions that produce carotenoid-based coloration in this species. Placing these comparisons in the framework of historical sequence of population establishment allows us to elucidate likely evolutionary trajectories of novel feather color phenotypes in this species.
Degree ProgramHonors College
Ecology and Evolutionary Biology