Meeting Abstract
Convergent evolution is the process by which similar traits arise independently under similar selective pressures. Understanding the mechanistic basis of convergence is a critical step towards understanding the repeatability and predictability of evolution. We used mice in the genus Peromyscus to explore the mechanistic basis of convergent evolution. Across North America, multiple species of Peromyscus have independently invaded high-altitude environments, which are characterized by severe and unremitting hypobaric hypoxia. Correspondingly, studies of the unique physiologies of high-altitude animals have provided clear examples of local adaptation and convergent evolution. However, it is yet unclear whether convergent solutions to hypoxia arise from the same or different underlying mechanisms. In this study, we acclimated six species of Peromyscus native to low- or high-altitude environments to both normoxia and hypobaric hypoxia for six weeks. We show that species native to high-altitude have evolved an adaptive blunting of hypoxia-induced increases in red blood cell production (erythropoiesis); in natives of low altitudes, hypoxia-induced erythropoiesis is maladaptive, often resulting in chronic disease or death. Measurements of gene expression reveal that transcriptomic variation is correlated with blunting of the erythropoietic response. Our results suggest that the elimination of maladaptive responses to hypoxia repeatedly evolves in independent high-altitude taxa and thus, is likely to be an important mechanism of local adaptation. The association of transcriptomic variation with phenotypic variation yields new insight into the regulatory mechanisms that drive adaptation of the erythropoietic response.
