DISSERTATION RESEARCH: Discovering the Evolutionary History of Nocturnality in Birds

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Historically, transitioning to a nocturnal lifestyle allowed some birds to operate during a time when fewer predators were active and there was less competition for food. Adaptation to nocturnality contributed to the great diversity of birds seen today and that transition likely began with the evolution of night vision. This research will develop a novel method to uncover the ways that birds adapted to see in the dark, and thus became nocturnal. This method incorporates detailed analyses of the genetic foundation of vision in all birds, and will help uncover other modes of avian diversification, such as the origin of diverse plumage coloration. The insights into bird vision gained through this research will be applicable and relevant to research on human vision and visual diseases, such as colorblindness. Little is known about night vision in birds, but phylogenetic analyses offer evidence of multiple independent origins of this trait and of nocturnality. The DNA sequence capture probe set developed in this proposal will allow isolation and sequencing of the entire phototransduction cascade from the genome of any bird. The phototransduction cascade is a pathway of approximately 30 genes, beginning with the absorption of a photon in an opsin, and resulting in the generation of a neural signal. For this project, these genes will be captured and sequenced from all major nocturnal bird lineages and their diurnal relatives. Analysis of these data will identify evidence of spectral tuning in opsins, evidence for selection, and potential loss or pseudogenization of genes in this cascade. This information will indicate how many times nocturnality has evolved across the avian tree of life, providing insight into the evolutionary origin of those adaptations, whether they were independently derived, represent convergent innovations, or are due to deep homology.