EVOLUTIONARY PROCESSES IN THE GENUS COREOCARPUS: INSIGHTS FROM MOLECULAR PHYLOGENETICS
EVOLUTIONARY PROCESSES IN THE GENUS COREOCARPUS: INSIGHTS FROM MOLECULAR PHYLOGENETICS
复制标题
核果属的进化过程：来自分子系统发育学的见解
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
E. B. Smith
中科院分区：
文献类型：
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作者：
R. Kimball;D. Crawford;E. B. Smith
摘要利用核（ITS）和质体（rp 116内含子）DNA序列对Coreocarpus属植物进行了分子系统学研究，核和质体序列的同源性高度一致，确定了一个单系群的6个种（核心Coreocarpus），尽管排除了其他3个常被置于该属内的种。该属内的关系在很大程度上，但不完全符合先前的生物系统学研究。尽管强有力的分子支持，没有形态特征团结的核心Coreocarpus的六个物种已被确定;保留的近形特征和遗传不稳定性的字符是两个可能的因素，导致缺乏一致的定义字符。核心Coreocarpus的年龄估计为100万年，因为基础物种是过去百万年出现的火山岛特有的。早期育种研究的分子系统发生学结果表明，使用杂交亲和性作为物种划分的标准将导致并系种的识别。先前的领域，形态学和生物系统学的研究没有提供任何迹象表明过去的杂交Coreocarpus的进化，和属中的物种似乎是很好的定义形态。然而，观察到三个不一致的情况。其中两个是核和质体分区之间，第三个是一个加入和分子数据之间的形态物种分配。如果杂交解释了核和质体数据之间的不一致，那么它发生在现在看来是杂交不亲和和异地分布的物种之间。形态学种分配和分子数据之间的不一致可能是具有简单遗传基础的性状的平行固定的结果。这一研究表明，Coreocarpus的进化历史比以往的生物系统学研究表明，更复杂，生物系统学和分子系统发育研究可以相互补充，以阐明一个组的进化和系统发育。
Abstract A molecular phylogenetic study of the plant genus Coreocarpus was conducted using nuclear (ITS) and plastid (rpl16 intron) DNA sequences, with phylogenies of the nuclear and plastid sequences highly congruent in defining a monophyletic group of six species (core Coreocarpus), although three other species often placed within the genus were excluded. Relationships within the genus are largely but not totally concordant with prior biosystematic studies. Despite strong molecular support, no morphological characters uniting the six species of core Coreocarpus have been identified; retention of plesiomorphic characters and the genetic lability of characters are two probable factors contributing to lack of consistent defining characters. The age of the core Coreocarpus is estimated at 1 million years because the basal species is endemic to a volcanic island that emerged in the past million years. Mapping the results of earlier breeding studies on the molecular phylogeny showed that use of cross-compatibility as a criterion for species delimitation would result in the recognition of paraphyletic species. Prior field, morphological, and biosystematic studies provided no indication of past hybridization in the evolution of Coreocarpus, and species in the genus appeared to be well defined morphologically. However, three instances of incongruence were observed. Two of these were between the nuclear and plastid partitions, and the third was between the morphological species assignment of one accession and the molecular data. If hybridization accounts for incongruence between the nuclear and plastid data, it occurred between species that now appear to be cross-incompatible and allopatric. The incongruence between morphological species assignment and the molecular data could be the result of parallel fixation of characters that have a simple genetic basis. This study suggests that the evolutionary history of Coreocarpus is much more complex than indicated from prior biosystematic investigations and that biosystematic and molecular phylogenetic studies may complement each other for elucidating the evolution and phylogeny of a group.