This project examines how core physiological and evolutionary processes shape biological diversity. Elucidating how genetic changes and selection pressures result in trait variation is a central goal of biology, and key to this is identifying the links between genes, form and function, and how these can alter the fitness of individuals and the evolutionary success of species. Moreover, understanding why and how many cellular and body structures have evolved independently in different species can explain how evolution takes multiple routes to 'solve' the same problem. <br/><br/>The biology of hair is an ideal system for studying these links between genetics, form and function. Hair is an anatomical trait that is shaped by both natural selection (e.g., providing camouflage against predators, protection from parasites, maintaining body temperature in cold environments) and sexual selection (e.g., signaling sex, age, status). It is a universal characteristic of mammals, yet across species there is striking variation in the color, pattern, growth, and texture of hair. Moreover, many hair traits, such as tail stripes or thick woolly coats, seem to have evolved repeatedly in different mammal lineages. Hair also is a trait for which small genetic differences can have major phenotypic effects; for example, red hair in humans is due to variation at a single gene. <br/><br/>This project applies cutting-edge genomic and comparative analyses to understand how genetic variation and selection have shaped this important anatomical feature (hair) in humans and other primates. In so doing, it also will provide a critical evolutionary context to understand one of the biological traits that make humans unique (relative hairlessness). Through conduct of the research, several undergraduate and graduate students, including individuals recruited from groups underrepresented in science, as well as a postdoctoral scholar, will receive extensive and broad scientific training. In addition, because many human and animal diseases are associated with hair changes and loss, this project is relevant for aspects of public health and dermatological and clinical research on hair/skin conditions. Animal hair also is an important commercial product; identifying the biological factors that shape hair characteristics in natural-living species could eventually improve the yield and quality of hair-based products. And finally, the project will generate a wealth of genetic and metric data on primate diversity that will contribute to research in conservation and evolutionary biology, as well as furthering research in biological anthropology.