Brinkmann Henner, Venkatesh Byrappa, Brenner Sydney, Meyer Axel
Department of Biology, University of Konstanz, 78457 Konstanz, Germany.
Proc Natl Acad Sci U S A. 2004 Apr 6;101(14):4900-5. doi: 10.1073/pnas.0400609101. Epub 2004 Mar 22.
The colonization of land by tetrapod ancestors is one of the major questions in the evolution of vertebrates. Despite intense molecular phylogenetic research on this problem during the last 15 years, there is, until now, no statistically supported answer to the question of whether coelacanths or lungfish are the closest living relatives of tetrapods. We determined DNA sequences of the nuclear-encoded recombination activating genes (Rag1 and Rag2) from all three major lungfish groups, the Australian Neoceratodis forsteri, the South American Lepidosiren paradoxa and the African lungfish Protopterus dolloi, and the Indonesian coelacanth Latimeria menadoensis. Phylogenetic analyses of both the single gene and the concatenated data sets of RAG1 and RAG2 found that the lungfishes are the closest living relatives of the land vertebrates. These results are supported by high bootstrap values, Bayesian posterior probabilities, and likelihood ratio tests.
四足动物祖先登陆是脊椎动物进化中的主要问题之一。尽管在过去15年里针对这个问题进行了深入的分子系统发育研究，但到目前为止，对于腔棘鱼或肺鱼是否是四足动物现存最近的亲属这一问题，尚无统计学支持的答案。我们测定了所有三个主要肺鱼群体（澳大利亚的新角齿鱼、南美洲的美洲肺鱼和非洲肺鱼）以及印度尼西亚腔棘鱼的核编码重组激活基因（Rag1和Rag2）的DNA序列。对RAG1和RAG2的单基因以及串联数据集进行系统发育分析发现，肺鱼是陆地脊椎动物现存最近的亲属。这些结果得到了高自展值、贝叶斯后验概率和似然比检验的支持。
