Tetrapod phylogeny inferred from 18S and 28S ribosomal RNA sequences and a review of the evidence for amniote relationships.
Tetrapod phylogeny inferred from 18S and 28S ribosomal RNA sequences and a review of the evidence for amniote relationships.
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DOI：
10.1093/oxfordjournals.molbev.a040628
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发表时间：
1990-11
影响因子：
10.7
通讯作者：
B. Hedges;K. D. Moberg;Linda
中科院分区：
文献类型：
--
作者：
B. Hedges;K. D. Moberg;Linda
对21个四足动物的18 S核糖体RNA进行测序，并与5个已发表的四足动物序列进行比对。当腔棘鱼被用作外类群时，Lissamphibia（活的两栖动物）和Amniota（Amniotes）被发现是统计学上显著的单系类群。虽然在利桑菲宾类的分类群中获得的分辨率很小，但这些序列支持鸟类和哺乳动物之间的姐妹群关系。部分的28 S核糖体RNA（rRNA）分子在11个四足动物也进行了测序，虽然系统发育的结果是不确定的。与以往的研究相比，碱基配对位点的缺失或降低权重对系统发育关系的影响不大。分子生物学证据的关系进行了审查，表明三个基因（β-血红蛋白，肌红蛋白，和18 S rRNA）明确支持鸟类与哺乳动物的关系，相比之下，一个基因（组蛋白H2 B），有利于鸟类鳄鱼的分支。对其他四个基因（α-晶状体蛋白A、α-血红蛋白、胰岛素和28 S rRNA）的单独分析和对所有序列数据的组合分析是不确定的，因为在不同的分析中定义了不同的组，没有一个得到有力的支持。有人建议，直到序列成为可从更广泛的类群，分子证据最好是在单个基因的水平进行评估，重点放在那些研究的类群和网站的最大数量。当这样做时，鸟类与哺乳动物的关系得到了最有力的支持。当结合形态学证据来考虑这种联系时，它至少应该被认为是像鸟类和鳄鱼的关系一样合理。
The 18S ribosomal RNAs of 21 tetrapods were sequenced and aligned with five published tetrapod sequences. When the coelacanth was used as an outgroup, Lissamphibia (living amphibians) and Amniota (amniotes) were found to be statistically significant monophyletic groups. Although little resolution was obtained among the lissamphibian taxa, the amniote sequences support a sister-group relationship between birds and mammals. Portions of the 28S ribosomal RNA (rRNA) molecule in 11 tetrapods also were sequenced, although the phylogenetic results were inconclusive. In contrast to previous studies, deletion or down-weighting of base-paired sites were found to have little effect on phylogenetic relationships. Molecular evidence for amniote relationships is reviewed, showing that three genes (beta-hemoglobin, myoglobin, and 18S rRNA) unambiguously support a bird-mammal relationship, compared with one gene (histone H2B) that favors a bird-crocodilian clade. Separate analyses of four other genes (alpha-crystallin A, alpha-hemoglobin, insulin, and 28S rRNA) and a combined analysis of all sequence data are inconclusive, in that different groups are defined in different analyses and none are strongly supported. It is suggested that until sequences become available from a broader array of taxa, the molecular evidence is best evaluated at the level of individual genes, with emphasis placed on those studies with the greatest number of taxa and sites. When this is done, a bird-mammal relationship is most strongly supported. When regarded in combination with the morphological evidence for this association, it must be considered at least as plausible as a bird-crocodilian relationship.