Genome-wide admixture and ecological niche modeling reveal the maintenance of species boundaries despite long history of interspecific gene flow

1.The maintenance of species boundaries despite interspecific gene flow has been a continuous source of interest in evolutionary biology. Many hybridizing species have porous genomes with regions impermeable to introgression, conferring reproductive barriers between species. 2.We used ecological niche modeling to study the glacial and postglacial recolonization patterns between the widely hybridizing spruce species Picea glauca and P. engelmannii in western North America. 3.Genome-wide estimates of admixture based on a panel of 311 candidate gene single nucleotide polymorphisms (SNP) from 290 genes were used to assess levels of admixture and introgression, and to identify loci putatively involved in adaptive differences or reproductive barriers between species. 4.Our paleoclimatic modeling suggests these two closely related species have a long history of hybridization and introgression, dating to at least 21,000 years ago, yet species integrity is maintained by a combination of strong e...1. 尽管存在种间基因流，物种边界的维持一直是进化生物学领域持续关注的研究热点。诸多发生杂交的物种拥有多孔化基因组，其部分区域对基因渐渗（introgression）具有抗性，进而在物种间形成生殖隔离。 2. 本研究借助生态位模型（ecological niche modeling），针对北美西部广泛杂交的云杉物种白云杉（Picea glauca）与恩氏云杉（Picea engelmannii）的冰期及冰期后再定植模式展开研究。 3. 本研究基于取自290个基因的311个候选基因单核苷酸多态性（single nucleotide polymorphisms, SNP）标记集，开展全基因组混合比例与基因渐渗水平评估，并鉴定出可能参与物种间适应性分化或生殖隔离的候选位点。 4. 本研究的古气候模型分析表明，这两个近缘物种的杂交与基因渐渗历史至少可追溯至2.1万年前，但物种完整性仍通过多种强...