Dauphin Benjamin, Vieu Julien, Grant Jason R
Laboratoire de botanique évolutive, Université de Neuchâtel, rue Emile-Argand 11, 2000 Neuchâtel, Switzerland.
Am J Bot. 2014 Jan;101(1):128-40. doi: 10.3732/ajb.1300154. Epub 2014 Jan 7.
Previous phylogenetic studies of moonworts (Botrychium sensu stricto (s.s.)) included few taxa from outside of North America. This low geographical representation limited interpretations of relationships of this group rich in cryptic species. With 18 out of 30 species in the genus being polyploid, understanding their evolutionary history remains a major challenge.
A new molecular phylogeny was reconstructed using Maximum Likelihood (ML) and Bayesian Inference (BI) analyses based on multiple accessions of the most wide-ranging Arctic taxa of Botrychium in North America and Europe using three noncoding plastid DNA regions (psbA-trnH(GUG), trnL(UAA)-trnF(GAA) intergenic spacer, and rpL16 intron).
The new phylogeny confirms the identity of several recently described species and proposed new taxa. Nine subclades are newly identified within the two major clades in Botrychium s.s.: Lanceolatum and Lunaria. Chloroplast DNA was variable enough to separate morphologically cryptic species in the Lunaria clade. On the contrary, much less variation is seen within the morphologically variable Lanceolatum clade despite sampling over the same broad geographic range. The chloroplast region psbA-trnH(GUG) is identified as an efficient DNA barcode for the identification of cryptic taxa in Botrychium s.s.
The combined increase in species representation, samples from throughout the geographic range of each species, and sequencing of multiple plastid DNA regions supports morphologically cryptic species in Botrychium s.s.
此前对阴地蕨属（狭义阴地蕨）的系统发育研究纳入的北美以外类群极少。这种低地理代表性限制了对这个富含隐存种的类群之间关系的解读。该属30个物种中有18个是多倍体，了解它们的进化历史仍是一项重大挑战。
基于北美和欧洲分布最广的北极阴地蕨类群的多个样本，利用三个非编码质体DNA区域（psbA-trnH(GUG)、trnL(UAA)-trnF(GAA)基因间隔区和rpL16内含子），通过最大似然法（ML）和贝叶斯推断（BI）分析重建了一个新的分子系统发育树。
新的系统发育树证实了几个最近描述的物种的身份，并提出了新的分类群。在狭义阴地蕨的两个主要分支：披针叶阴地蕨分支和月状阴地蕨分支内新确定了九个亚分支。叶绿体DNA的变异性足以区分月状阴地蕨分支中形态上的隐存种。相反，尽管在相同的广泛地理范围内进行了采样，但在形态多变的披针叶阴地蕨分支内观察到的变异要少得多。叶绿体区域psbA-trnH(GUG)被确定为鉴定狭义阴地蕨中隐存分类群的有效DNA条形码。
物种代表性的增加、每个物种地理范围内样本的增加以及多个质体DNA区域的测序相结合，支持了狭义阴地蕨中形态上的隐存种。
