Multigene phylogeny of land plants with special reference to bryophytes and the earliest land plants
Multigene phylogeny of land plants with special reference to bryophytes and the earliest land plants
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DOI：
10.1093/oxfordjournals.molbev.a026290
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发表时间：
2000-12-01
影响因子：
10.7
通讯作者：
Duff, RJ
中科院分区：
文献类型：
--
作者：
Nickrent, DL;Parkinson, CL;Duff, RJ
地钱是陆地植物的第一个分支，而分子生物学分析和形态学特征的分支研究表明，金鱼藻是最早的陆地植物。为了帮助解决这一冲突，我们使用简约和似然方法分析了一个6,095个字符的数据集，该数据集由来自所有主要陆地植物谱系的四个基因（叶绿体rbcL和来自所有三个植物基因组的小亚基rDNA）组成。在所有的分析中，获得显着的支持单系的维管植物，石松，蕨类植物（包括Psilotum和木贼），种子植物和被子植物。在简约分析中，所有职位都被包括在内，权重相等，这三个brittete血统之间的关系没有得到解决。然而，在简约性和可能性分析中，rbcL第三密码子位置转换被排除或降低权重（由于明显的饱和），金鱼藻被放置为所有其他陆地植物的姐妹，苔藓和地钱共同形成第二深的谱系。衰变分析和Kishino-Hasegawa测试的第三个位置排除的数据集显示显着支持金鱼藻基础拓扑结构的几种替代拓扑结构，包括常用的地钱基础拓扑结构。在所使用的四个基因中，线粒体小亚基rDNA表现出最低的同源性和单独恢复基本上相同的拓扑结构的多基因树。这种分子生物学为评估陆生植物早期进化过程中发生的古生物学证据和形态学创新提供了新的机会。
A widely held view of land plant relationships places liverworts as the first branch of the land plant tree, whereas some molecular analyses and a cladistic study of morphological characters indicate that hornworts are the earliest land plants. To help resolve this conflict, we used parsimony and likelihood methods to analyze a 6,095-character data set composed of four genes (chloroplast rbcL and small-subunit rDNA from all three plant genomes) from all major land plant lineages. In all analyses, significant support was obtained for the monophyly of vascular plants, lycophytes,ferns (including Psilotum and Equisetum), seed plants, and angiosperms. Relationships among the three bryophyte lineages were unresolved in parsimony analyses in which all positions were included and weighted equally. However, in parsimony and likelihood analyses in which rbcL third-codon-position transitions were either excluded or downweighted (due to apparent saturation), hornworts were placed as sister to all other land plants, with mosses and liverworts jointly forming the second deepest lineage. Decay analyses and Kishino-Hasegawa tests of the third-position-excluded data set showed significant support for the hornwort-basal topology over several alternative topologies, including the commonly cited liverwort-basal topology. Among the four genes used, mitochondrial small-subunit rDNA showed the lowest homoplasy and alone recovered essentially the same topology as the multigene tree. This molecular phylogeny presents new opportunities to assess paleontological evidence and morphological innovations that occurred during the early evolution of terrestrial plants.