Evolutionary divergence on the Qinghai-Tibet Plateau: How life-history traits shape the diversity of plateau zokor and pika populations.

Abstract

Understanding how species diverge and adapt is fundamental to unraveling biodiversity. While environmental impacts on species evolution are well-documented, the roles of intrinsic life-history traits remain underexplored. The Qinghai-Tibet Plateau, with its harsh conditions and unique biodiversity, offers a natural laboratory for such investigations. Here, we examined two sympatric small mammals-the solitary, low-dispersal plateau zokor (Eospalax baileyi) and the social, high-dispersal plateau pika (Ochotona curzoniae)-to elucidate how life-history traits shape population structures and adaptive strategies. Through whole-genome sequencing and cardiac-blood phenotype analyses, we reveal striking differences in their evolutionary trajectories. Despite enduring similar environmental pressures, plateau zokor populations exhibit pronounced genetic subdivisions, high inbreeding, and distinct local adaptations. In contrast, plateau pika populations display genetic panmixia, widespread diversity, and adaptive uniformity. Demographic inference highlights plateau zokors experienced severe population bottlenecks and restricted gene flow during glacial periods, underscoring the impact of dispersal capacity on evolutionary outcomes. Our findings demonstrate that intrinsic biological traits, particularly dispersal ability, fundamentally influence genetic architecture, population connectivity, and local adaptation. This study not only provides empirical evidence of how life-history traits shape evolutionary dynamics but also offers a framework for integrating intrinsic and extrinsic factors in understanding biodiversity formation.