A molecular phylogenetic stud of Arnica (Asteraceae):: Low chloroplast DNA variation and problematic subgeneric classification
A molecular phylogenetic stud of Arnica (Asteraceae):: Low chloroplast DNA variation and problematic subgeneric classification
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DOI：
10.1600/036364407783390728
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发表时间：
2007-10-01
影响因子：
1
通讯作者：
Andreasen, Katarina
中科院分区：
文献类型：
--
作者：
Ekenas, Catarina;Baldwin, Bruce G.;Andreasen, Katarina
利用最大简约法和贝叶斯方法分析了5个叶绿体DNA区域（rp 116和rps 16内含子以及psbA-trnH、ycf 4-cemA和trnT-L间隔区）和核核糖体内转录间隔区（ITS和ETS）的DNA序列，以探讨北美山金车属（Arnica）的复杂演化历史。叶绿体区域被发现含有山金车最小的变化。在3710个核苷酸中，只有119个是可变的，45个是信息的。然而，结合核糖体DNA数据，分析产生了一些支持良好的分支。山金车的单系性的强有力的支持，发现在单独和合并的分析，但没有五个目前公认的亚属被解决为单系的任何分析。山金车（Arnica（Whitneya）dealbata）和山金车A.先前在山金车属以外的两个种-马洛托普斯属（Malotopus）被确信地确认为该属的成员。分析表明，A. nevadensis（subg. Austromontana）与A. dealbata和A. mallotopus与A. unalaschcensis（subg. Andropurpurea）。早期的地理学假说，建议北极起源和向南传播的属不支持我们的分析。杂交，同质性，和快速进化的叶绿体和核核糖体数据集之间的冲突和低支持的更深的节点可能的解释。
DNA sequences from five chloroplast DNA regions (the rpl16 and rps16 introns and the psbA-trnH, ycf4-cemA, and trnT-L spacers), and the nuclear ribosomal internal and external transcribed spacer (ITS and ETS) regions, were analyzed using maximum parsimony and Bayesian methods to explore the putatively complicated history of the mainly North American genus Arnica. The chloroplast regions were found to contain minimal variation in Arnica. Of 3710 nucleotides, only 119 were variable and 45 informative. However, combined with the ribosomal DNA data, the analysis yielded a number of well-supported clades. Strong support for the monophyly of Arnica was found in both the separate and combined analyses but none of the five currently recognized subgenera was resolved as monophyletic in any of the analyses. Arnica (Whitneya) dealbata and A. mallotopus (Mallotopus japonicus), two species that were previously placed outside Arnica, were confidently confirmed as members of the genus. The analyses revealed that A. nevadensis (subg. Austromontana) is most closely related to A. dealbata and that A. mallotopus forms a strongly supported clade with A. unalaschcensis (subg. Andropurpurea). Earlier biogeographical hypotheses that suggested an arctic origin and southward spread of the genus are not supported by our analyses. Hybridization, homoplasy, and rapid evolution are possible explanations for conflicts between the chloroplast and nuclear ribosomal data sets and for low support of the deeper nodes.