Yu Shuiyan, Zhang Weiwei, Li Ling, Huang Huifang, Ma Fei, Li Qingwei
Institute of Marine Genomics & Proteomics, Liaoning Normal University, Dalian 116029, China.
J Genet Genomics. 2008 May;35(5):285-90. doi: 10.1016/S1673-8527(08)60041-7.
It has become clear that the extant vertebrates are divided into three major groups, that is, hagfishes, lampreys, and jawed vertebrates. Morphological and molecular studies, however, have resulted in conflicting views with regard to their interrelationships. To clarify the phylogenetic relationships between them, 48 orthologous protein-coding gene families were analyzed. Even as the analysis of 34 nuclear gene families supported the monophyly of cyclostomes, the analysis of 14 mitochondrial gene families suggested a closer relationship between lampreys and gnathostomes compared to hagfishes. Lampreys were sister group of gnathostomes. The results of this study supported the cyclostomes. Choice of outgroup, tree-making methods, and software may affect the phylogenetic prediction, which may have caused much debate over the subject. Development of new methods for tackling such problems is still necessary.
现已明确，现存的脊椎动物分为三大类，即盲鳗、七鳃鳗和有颌脊椎动物。然而，形态学和分子研究在它们的相互关系上产生了相互矛盾的观点。为了阐明它们之间的系统发育关系，对48个直系同源蛋白质编码基因家族进行了分析。尽管对34个核基因家族的分析支持圆口纲动物的单系性，但对14个线粒体基因家族的分析表明，与盲鳗相比，七鳃鳗和有颌类动物之间的关系更为密切。七鳃鳗是有颌类动物的姐妹群。本研究结果支持圆口纲动物。外类群的选择、建树方法和软件可能会影响系统发育预测，这可能导致了对此主题的诸多争论。开发解决此类问题的新方法仍然很有必要。
