Geographic variability of hybridization between red-breasted and red-naped sapsuckers

Hybrid zones reveal the strength of reproductive isolation between populations undergoing speciation and are a key tool in evolutionary biology research. Multiple replicate transects across the same hybrid zone offer insight into the dynamics of hybridization in different environments, clarifying the role of extrinsic forces on the speciation process. Red-breasted and red-naped sapsuckers (Sphyrapicus ruber and S. nuchalis) have a long zone of contact over approximately 1,600 km from central British Columbia, Canada to central California, USA. We used Genotyping-by-Sequencing data from three independent sapsucker hybrid zone transects to compare hybridization dynamics between these species under variable geoclimatic conditions. We generated geographic clines of the genomic data to compare hybrid zone widths and used Random Forest models and linear regression to assess the relationship between climate and sapsucker ancestry along each transect. Our results show variation in the direction...

杂交带（hybrid zone）能够揭示正在经历物种形成的种群间生殖隔离的强度，是进化生物学研究中的关键工具。对同一杂交带开展多次重复样带调查，可深入解析不同环境下的杂交动态，阐明外在环境作用力在物种形成进程中的作用。红胸吸汁啄木鸟（Sphyrapicus ruber）与红颈吸汁啄木鸟（S. nuchalis）的接触带跨度约1600公里，分布范围从加拿大不列颠哥伦比亚省中部延伸至美国加利福尼亚州中部。本研究利用来自3条独立吸汁啄木鸟杂交带样带的基因型分型测序（Genotyping-by-Sequencing）数据，对比不同地理气候条件下这两个物种的杂交动态。我们通过基因组数据构建地理渐变群以对比杂交带宽度，并采用随机森林（Random Forest）模型与线性回归方法，评估每条样带沿线气候与吸汁啄木鸟祖先遗传组分之间的关联。本研究结果显示在该方向上存在变异……