Wang Xumei, Gussarova Galina, Ruhsam Markus, de Vere Natasha, Metherell Chris, Hollingsworth Peter M, Twyford Alex D
School of Pharmacy, Xi'an Jiaotong University, Xi'an, P.R. China.
Tromsø University Museum, UiT The Arctic University of Norway, Langnes, Tromsø, Norway.
AoB Plants. 2018 Apr 24;10(3):ply026. doi: 10.1093/aobpla/ply026. eCollection 2018 Jun.
DNA barcoding is emerging as a useful tool not only for species identification but also for studying evolutionary and ecological processes. Although plant DNA barcodes do not always provide species-level resolution, the generation of large DNA barcode data sets can provide insights into the mechanisms underlying the generation of species diversity. Here, we study evolutionary processes in taxonomically complex British (Orobanchaceae), a group with multiple ploidy levels, frequent self-fertilization, young species divergence and widespread hybridization. We use a phylogenetic approach to investigate the colonization history of British , followed by a DNA barcoding survey and population genetic analyses to reveal the causes of shared sequence variation. Phylogenetic analysis shows have colonized Britain from mainland Europe on multiple occasions. DNA barcoding reveals that no British species has a consistent diagnostic sequence profile, and instead, plastid haplotypes are either widespread across species, or are population specific. The partitioning of nuclear genetic variation suggests differences in ploidy act as a barrier to gene exchange, while the divergence between diploid and tetraploid ITS sequences supports the polyploids being allotetraploid in origin. Overall, these results show that even when lacking species-level resolution, analyses of DNA barcoding data can reveal evolutionary patterns in taxonomically complex genera.
DNA条形码正逐渐成为一种有用的工具,不仅可用于物种鉴定,还能用于研究进化和生态过程。尽管植物DNA条形码并不总能提供物种水平的分辨率,但大量DNA条形码数据集的生成能够为物种多样性产生的潜在机制提供见解。在此,我们研究分类复杂的英国列当属(列当科)的进化过程,该类群具有多个倍性水平、频繁的自花受精、物种分化时间短且杂交广泛。我们采用系统发育方法来研究英国列当属的定殖历史,随后进行DNA条形码调查和群体遗传学分析,以揭示共享序列变异的原因。系统发育分析表明,列当属多次从欧洲大陆定殖到英国。DNA条形码显示,没有英国列当属物种具有一致的诊断序列特征,相反,质体单倍型要么在物种间广泛分布,要么具有种群特异性。核基因变异的划分表明倍性差异是基因交换的障碍,而二倍体和四倍体ITS序列之间的差异支持多倍体起源于异源四倍体。总体而言,这些结果表明,即使缺乏物种水平的分辨率,对DNA条形码数据的分析也能揭示分类复杂属中的进化模式。