Skip to main content
Dryad

Evidence for admixture and rapid evolution during glacial climate change in an alpine specialist

Data files

Apr 23, 2024 version files 11.39 GB

Abstract

The pace of current climate change is expected to be problematic for alpine flora and fauna, as their adaptive capacity may be limited by small population size. Yet despite substantial genetic drift following post-glacial recolonization of alpine habitats, alpine species are notable for their success in surviving highly heterogeneous environments. Population genomic analyses demonstrating how alpine species have adapted to novel environments with limited genetic diversity remain rare, yet are important in understanding the potential for species to respond to contemporary climate change. In this study, we explored the evolutionary history of alpine ground beetles in the Nebria ingens complex, including the demographic and adaptive changes that followed the last glacier retreat. We first tested alternative models of evolutionary divergence in the species complex. Using the millions of genome-wide SNP markers from hundreds of beetles, we found evidence that the Nebria ingens complex has been formed by past admixture of lineages responding to glacial cycles. Recolonization of alpine sites involved a distributional range shift to higher elevation, which was accompanied by a reduction in suitable habitat and the emergence of complex spatial genetic structure. We tested several possible genetic pathways involved in the adaptation to heterogeneous local environments using whole genome scan and genotype-environment association approach. From the identified genes, we found enriched functions broadly associated with abiotic stress responses, with strong evidence for adaptation to hypoxia-related pathways. The results demonstrate that despite rapid environmental changes, alpine beetles in the N. ingens complex have shown rapid physiological evolution.