Data from: Vive la résistance: genome-wide selection against introduced alleles in invasive hybrid zones

Evolutionary and ecological consequences of hybridization between native and invasive species are notoriously complicated because patterns of selection acting on non-native alleles can vary throughout the genome and across environments. Rapid advances in genomics now make it feasible to assess locus-specific and genome-wide patterns of natural selection acting on invasive introgression within and among natural populations occupying diverse environments. We quantified genome-wide patterns of admixture across multiple independent hybrid zones of native westslope cutthroat trout and invasive rainbow trout, the world's most widely introduced fish, by genotyping 339 individuals from 21 populations using 9380 species-diagnostic loci. A significantly greater proportion of the genome appeared to be under selection favouring native cutthroat trout (rather than rainbow trout), and this pattern was pervasive across the genome (detected on most chromosomes). Furthermore, selection against invasive alleles was consistent across populations and environments, even in those where rainbow trout were predicted to have a selective advantage (warm environments). These data corroborate field studies showing that hybrids between these species have lower fitness than the native taxa, and show that these fitness differences are due to selection favouring many native genes distributed widely throughout the genome.

本土物种与入侵物种间的杂交所引发的进化与生态后果素来复杂棘手，这是因为作用于外来等位基因的选择模式，可在全基因组范围内以及不同生境间存在显著差异。如今基因组学领域的飞速进展，使得我们能够在占据多样生境的自然种群内部及种群之间，评估作用于入侵性基因渐渗（introgression）的位点特异性与全基因组范围的自然选择模式。我们采用9380个物种诊断性位点（species-diagnostic loci），对来自21个种群的339个个体进行基因分型，量化了本土西坡割喉鳟（westslope cutthroat trout）与全球引种范围最广的入侵鱼类虹鳟（rainbow trout）之间多个独立杂交带的全基因组遗传混合模式。结果显示，显著更高比例的基因组区域处于偏向本土割喉鳟而非虹鳟的选择作用之下，且这一模式在全基因组范围内广泛分布（多数染色体上均有检测到）。此外，针对入侵等位基因的选择在不同种群与生境间均保持一致，即便在那些理论上虹鳟具有选择优势的生境（如温暖环境）中亦是如此。本研究数据佐证了野外研究的结论：这两个物种的杂交后代适合度（fitness）低于本土类群，并揭示了这类适合度差异源于对广泛分布于全基因组的众多本土基因的选择偏向。