Multi-locus analysis of Pristionchus pacificus on La Réunion Island reveals an evolutionary history shaped by multiple introductions, constrained dispersal events, and rare out-crossing

Pristionchus pacificus, recently established as a model organism in evolutionary biology, is a cosmopolitan nematode that has a necromenic association with scarab beetles. The diverse array of host beetle species and habitat types occupied by P. pacificus make it a good model for investigating local adaptation to novel environments. The presence of P. pacificus on La Réunion Island, a young volcanic island with a dynamic geological history and a wide variety of ecozones, facilitates such investigation in an island biogeographical setting. Microsatellite data from 20 markers and 223 strains, and mitochondrial sequence data from 272 strains, reveal rich genetic diversity among La Réunion P. pacificus isolates, shaped by differentially timed introductions from diverse sources and in association with different beetle species. Distinctions between volcanic zones, and between arid western and wet eastern climatic zones, have likely limited westwards dispersal of recently colonised lineages, a...

太平洋新杆线虫（Pristionchus pacificus）是近年来被确立为进化生物学领域模式生物的广布性线虫，与金龟子存在尸生共生关系。该线虫可寄生多样的金龟子宿主类群并栖息于多种生境类型中，使其成为研究生物对新生环境局部适应机制的理想模型。留尼旺岛（La Réunion）是一座地质历史活跃的年轻火山岛，拥有丰富多样的生态区系，该线虫在留尼旺岛的分布为岛屿生物地理学框架下的相关研究提供了便利条件。研究团队通过20个微卫星（microsatellite）标记位点的223株线虫的微卫星数据，以及272株线虫的线粒体序列数据，揭示了留尼旺岛太平洋新杆线虫分离株中丰富的遗传多样性——该多样性由不同来源、不同时期的多次引入事件塑造，且与不同的金龟子宿主类群相关。火山带之间以及西部干旱与东部湿润气候区之间的地理差异，可能限制了新近定殖的谱系向西扩散，……