Molecular phylogenetics and morphological evolution of St. John's wort (Hypericum; Hypericaceae)
Molecular phylogenetics and morphological evolution of St. John's wort (Hypericum; Hypericaceae)
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DOI：
10.1016/j.ympev.2012.08.022
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发表时间：
2013-01-01
影响因子：
4.1
通讯作者：
Blattner, Frank R.
中科院分区：
文献类型：
--
作者：
Nuerk, Nicolai M.;Madrinan, Santiago;Blattner, Frank R.
大世界性属金丝桃（圣约翰麦芽汁）的系统发育假说以前是基于形态学，分子研究迄今只包括少数物种。在这项研究中，我们使用了代表金丝桃属206种植物（包括金丝桃属）的核核糖体DNA（nrDNA）内转录间隔区（ITS）区域的360个序列。Triadenum和Thomea）和金丝桃科其他三个属，以产生一个明确的系统发育假说的属使用简约和基于模型的方法。结果表明，小属三腺草嵌套在金丝桃属的一个分支内，包含了大多数新大陆物种。金丝桃属的姐妹是来自中美洲的托梅亚。在金丝桃属中，发现了三个大的分支和两个较小的等级;这些是基于它们的一般形态，特别是以前在属的分类中使用的特征。相对于最近的分类，约60%的金丝桃属的组是单系的。我们使用贝叶斯方法来重建选定的形态特征的祖先状态，这导致识别的字符，支持属内的主要分支和修改后的解释形态进化金丝桃属。灌木状的习性代表了草本植物经过几次进化后的近形状态。乔木物种在热带非洲和南美洲的高海拔栖息地辐射收敛。(C)2012 Elsevier Inc. All rights reserved.
Phylogenetic hypotheses for the large cosmopolitan genus Hypericum (St. John's wort) have previously been based on morphology, and molecular studies have thus far included only a few species. In this study, we used 360 sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA) for 206 species representing Hypericum (incl. Triadenum and Thomea) and three other genera of Hypericaceae to generate an explicit phylogenetic hypothesis for the genus using parsimony and model-based methods. The results indicate that the small genus Triadenum is nested in a clade within Hypericum containing most of the New World species. Sister to Hypericum is Thomea from Central America. Within Hypericum, three large clades and two smaller grades were found; these are based on their general morphology, especially characters used previously in taxonomy of the genus. Relative to the most recent classification, around 60% of the sections of Hypericum were monophyletic. We used a Bayesian approach to reconstruct ancestral states of selected morphological characters, which resulted in recognition of characters that support major clades within the genus and a revised interpretation of morphological evolution in Hypericum. The shrubby habit represents the plesiomorphic state from which herbs evolved several times. Arborescent species have radiated convergently in high-elevation habitats in tropical Africa and South America. (C) 2012 Elsevier Inc. All rights reserved.