Data from: Genetic diversity and evolutionary history of four closely related Aquilegia species revealed by ten nuclear gene fragments

Recently the genus Aquilegia is emerging as the new model system for plant development, ecology and evolution studies. Previous researches demonstrated that pollinator shift might drive the diversification of North American Aquilegia species and natural selection on the length of spur might play a crucial role. In this genus, A. ecalcarata is the only taxon which has lost spur and nectar on the petal. Previous phylogenetic result indicated that A. ecalcarata, A. yabeana, A. oxysepala var. kansuensis and A. rockii comprised a monophyletic group. However, the genetic diversity pattern of them remains unknown. Besides, little is known about the evolutionary relationship among the four species on population level. Here we carried out a population genetics study with 21 representative populations based on 10 single-copy nuclear gene fragments and found out: 1) A. yabeana conserved the highest genetic diversity (both πsil and θsil) while A. oxysepala var. kansuensis had the lowest level; 2) A. ecalcarata splitted into two groups with one population clustered with A. rockii and the rest five populations clustered with A. oxysepala var. kansuensis; 3) allele frequency spectrum showed an excess of low frequency alleles in all four species, implying that they may undergo the mutation-drift equilibrium. Our findings provide the first investigation of genetic diversity and evolutionary relationship in A. yabeana, A. oxysepala var. kansuensis, A. rockii, A. ecalcarata, and lay foundation for future evolutionary studies like speciation mediated by pollinators.

近年来，耧斗菜属（Aquilegia）正逐渐成为植物发育学、生态学与进化生物学研究的新兴模式系统。既往研究表明，传粉者转变（pollinator shift）可能推动了北美耧斗菜属物种的分化，而花距（spur）长度所受的自然选择或发挥关键作用。在该属中，无距耧斗菜（A. ecalcarata）是唯一一种花瓣丢失花距与花蜜的类群。既往系统发育（phylogenetic）研究结果表明，无距耧斗菜（A. ecalcarata）、华北耧斗菜（A. yabeana）、尖萼耧斗菜甘肃变种（A. oxysepala var. kansuensis）以及秦岭耧斗菜（A. rockii）构成一个单系群（monophyletic group）。然而，这四个类群的遗传多样性模式仍未明确。此外，在种群水平上，这四个物种间的演化关系也鲜有研究。本研究基于10个单拷贝核基因片段（single-copy nuclear gene fragments），对21个代表性种群开展了种群遗传学分析，结果如下：1）华北耧斗菜（A. yabeana）的遗传多样性（包括同义位点核苷酸多样性πsil与沉默位点Watterson统计量θsil）最高，而尖萼耧斗菜甘肃变种（A. oxysepala var. kansuensis）的遗传多样性水平最低；2）无距耧斗菜（A. ecalcarata）可划分为两个类群：其中一个种群与秦岭耧斗菜（A. rockii）聚为一支，其余五个种群则与尖萼耧斗菜甘肃变种聚为一支；3）所有四个物种的等位基因频率谱（allele frequency spectrum）均显示低频等位基因过量，暗示它们可能处于突变-漂移平衡（mutation-drift equilibrium）状态。本研究首次对华北耧斗菜、尖萼耧斗菜甘肃变种、秦岭耧斗菜以及无距耧斗菜的遗传多样性与演化关系进行了系统探究，为后续诸如传粉者介导的物种形成等演化生物学研究奠定了基础。