The impacts of polyploidy, geographic and ecological isolations on the diversification of Panax (Araliaceae).
The impacts of polyploidy, geographic and ecological isolations on the diversification of Panax (Araliaceae).
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DOI：
10.1186/s12870-015-0669-0
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发表时间：
2015-12-21
影响因子：
5.3
通讯作者：
Li LF
中科院分区：
文献类型：
--
作者：
Shi FX;Li MR;Li YL;Jiang P;Zhang C;Pan YZ;Liu B;Xiao HX;Li LF
[医]人参属是五加科中一个重要的药用属，几乎所有的物种都是传统中药的文化意义。以往的研究表明，该属存在东亚和北美两个独立的起源、间断分布和多轮的全基因组复制（WGD）。本研究利用多个叶绿体和核标记对人参属植物的进化和多样性进行了研究。我们的系统发育分析证实了以前的观察独立的起源间断分布和古代和最近的WGD发生在人参。对分歧时间的估计表明，古WGD可能发生在人参属植物建立之前。此后，在人参中至少发生了两次独立的WGD事件，其中一次导致了三个地理上隔离的四倍体物种人参、人参和西洋参的形成。群体遗传分析表明，二倍体三七的核苷酸多样性显著低于四倍体人参和西洋参，且三种三七在外显子区域的核苷酸变异模式不同。基于系统发育和居群遗传分析，结合人参属植物的物种分布格局，我们的研究结果表明，两轮WGD沿着地理和生态隔离可能共同促进了该属植物的进化和多样性。本文的在线版本（doi：10.1186/s12870-015-0669-0）包含补充材料，可供授权用户使用。
Panax L. is a medicinally important genus within family Araliaceae, where almost all species are of cultural significance for traditional Chinese medicine. Previous studies suggested two independent origins of the East Asia and North America disjunct distribution of this genus and multiple rounds of whole genome duplications (WGDs) might have occurred during the evolutionary process. We employed multiple chloroplast and nuclear markers to investigate the evolution and diversification of Panax. Our phylogenetic analyses confirmed previous observations of the independent origins of disjunct distribution and both ancient and recent WGDs have occurred within Panax. The estimations of divergence time implied that the ancient WGD might have occurred before the establishment of Panax. Thereafter, at least two independent recent WGD events have occurred within Panax, one of which has led to the formation of three geographically isolated tetraploid species P. ginseng, P. japonicus and P. quinquefolius. Population genetic analyses showed that the diploid species P. notoginseng harbored significantly lower nucleotide diversity than those of the two tetraploid species P. ginseng and P. quinquefolius and the three species showed distinct nucleotide variation patterns at exon regions. Our findings based on the phylogenetic and population genetic analyses, coupled with the species distribution patterns of Panax, suggested that the two rounds of WGD along with the geographic and ecological isolations might have together contributed to the evolution and diversification of this genus. The online version of this article (doi:10.1186/s12870-015-0669-0) contains supplementary material, which is available to authorized users.