Population history of the golden eagle inferred from whole-genome sequencing of three of its subspecies

Abstract

AbstractThe application of evolutionary genetic research to investigate the potential for endangered species to adapt to changing environments is important for conservation biology. Effective population size (Ne) is informative for understanding adaptive potential as it refers to the genetic variation in breeding individuals who have contributed to contemporary and historic population diversity. We reconstruct fluctuations in Ne in three golden eagle subspecies (Japanese, Scottish, North American) using the pairwise sequential Markovian coalescent (PSMC) model based on whole-genome sequence data. Our results indicate the timing of subspeciation events and suggest significant ongoing demographic reductions since the start of the Last Glacial Period. Importantly, we find evidence for gene flow from continental populations into the ancestral Japanese population resulting in a short, sharp recovery in genetic diversity. Timing agrees with the palaeogeographic estimates of land bridge connections between the Japanese archipelago and Asian continent and matches a similar Ne spike in the Scottish population, but not in the North American population. Given contemporary declines in isolated Japanese and UK island populations, our study highlights a concerning loss of local genetic diversity, but also indicates the likely response of populations to genetic reinforcement from neighbouring subspecies, increasing management options and encouraging a range-wide species conservation approach.