Coat color variation can provide distinct adaptive benefits to wild mammalian species. Differences in the amount or distribution of pigment can produce striking phenotypic variation, often helping the animal to hide from or to warn potential predators, hunt prey, attract a mate, or even conserve body heat. Within the past decade there has been considerable progress in understanding the molecular mechanisms and evolutionary history that underlie coat color variation in mammals. The purpose of this thesis is to further examine the adaptive significance of coat color in mammals and to identify the genetic basis of coat color variation in a specific natural population. In addition, the roles of numerous genes known to be involved in the pigmentation pathway are examined in dogs, with the hope of better understanding the genetic basis for coat color differences in canines. The ultimate goal of this research is to develop a better understanding of the genetics of adaptation in the context of selection on the basis of coat color. I have identified the KB allele of the K locus as the cause of black coat color in North American gray wolves and coyotes. The KB allele was introduced into the wolf population through introgression with dogs. In forested regions of North America the KB allele has proven to be advantageous to wolves, and has experienced strong positive selection. This research provides a unique example of a trait that was developed and selected for by humans introgressing into a natural population where it proved to be advantageous.;I have performed a comprehensive study of seven pigmentation genes in dogs, wolves, and often coyotes and African Wild Dogs. We were able to observe patterns of mutations at there loci amongst several highly related species, and in the case of Mc1r and Pmel17, identify possible signatures of selection. This research will aid in the identification of components of the pigmentation pathway in canines and further the study of evolution of diverse morphological traits. The last part of my thesis contains an article that reviews the genetics of coat color in dogs and mammals. This chapter uses dogs as a model for the study of coat color genetics, and describes loci responsible for color differences in a range of mammalian species.;This work will help us to understand how adaptation occurs in natural populations, and adds to our understanding of the pigmentation pathway in both domestic dogs and natural canine populations.
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