The evolution of ancestral and species-specific adaptations in snowfinches at the Qinghai–Tibet Plateau

Abstract

Significance Harsh conditions in high elevations present strong stresses for organisms. Previous studies targeting phylogenetically distinct species revealed cases of diversified adaptations, but it remains largely unknown how common ancestry contributes to evolution of similar adaptations. Our study based on a species complex (snowfinches) living on Qinghai–Tibet Plateau shows that ancestral snowfinches had phenotypically evolved larger body size and genetically an accelerated selection on genes related to development and signaling. From this ancestral state of adaptation three descendants have undergone independent adaptive processes in response to the differences in selective pressures acting on them. A striking example is a DNA repair gene, DTL , in which nonsynonymous substitutions evolving in ancestor and descendants have led to different DNA damage repair kinetics.