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    由8个DNA片段推断云南金钱槭的系统位置

    Systematic position of Dipteronia dyerana inferred from eight gene regions

    • 摘要: 云南金钱槭是金钱槭属中的濒危物种,其系统地位迄今存在一定争议。本研究利用6个叶绿体基因片段(psbM-trnD、rbcL、trnD-trnT、rpl16、trnL-trnF与psbA-trnH)和2个核基因片段(ITS与CHS)数据,采用最大简约法(MP)及贝叶斯法(BI)对该种及若干近缘类群进行了系统发育分析,从而探讨云南金钱槭的系统位置。结果显示:1)基于6个叶绿体基因联合数据分析,云南金钱槭所在的金钱槭属形成单系群并与槭属彼此独立,互为姐妹属。2)基于CHS数据分析,金钱槭属物种自身形成单系群,但与槭属物种混在一起。3)基于ITS数据分析,金钱槭属为并系群,其中云南金钱槭内嵌于系统发育树的末端与梣叶槭聚在同一进化分枝。本研究中,不同数据集的结果出现冲突,可能是由于不同基因片段进化速率存在差异的影响。此外,核CHS基因在槭树科植物中的有效变异信息位点较少以及核ITS基因存在多拷贝的现象,均可能造成与6个叶绿体基因组合的分析结果出现差异。综合研究结果并参考形态学证据,倾向于云南金钱槭的系统位置继续归属于金钱槭属。进一步增加基因片段可能有助于云南金钱槭系统位置的明确。

       

      Abstract: Dipteronia dyerana is one of the endangered species of genus Dipteronia, and its phylogenetic placement is still in dispute thus far. To access the systematic placement of D. dyerana, the sequences of ITS, CHS, psbM-trnD spacer, rbcL, trnD-trnT spacer, rpl16 intron, trnL-trnF spacer and psbA-trnH spacer regions from the target species were analyzed using parsimony and Bayesian inference methods. The results showed that: 1) The Dipteronia was a monophyletic lineage in six chloroplast DNA genes combined. 2) In CHS, Dipteronia was a monophyletic lineage, but had a fuzzy relationship with Acer spp. 3) D. dyerana nested in Acer and Dipteronia was a paraphyletic lineage in ITS. These results indicated that different data sets had a conflict result, it may be due to different rates of each gene fragment evolution. Less informative sites in CHS and the multicopy in ITS may be the reason why they have different result with six chloroplast DNA genes combined. Integrated research results and morphological evidence, systematic placement of D. dyerana should belong to Dipteronia. Moreover, much more genes should be chosen when study on systematic placement of D. dyerana.

       

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