DETAILS OF THE EVOLUTIONARY HISTORY FROM INVERTEBRATES TO VERTEBRATES, AS DEDUCED FROM THE SEQUENCES OF 18S RDNA
DETAILS OF THE EVOLUTIONARY HISTORY FROM INVERTEBRATES TO VERTEBRATES, AS DEDUCED FROM THE SEQUENCES OF 18S RDNA
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DOI：
10.1073/pnas.91.5.1801
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发表时间：
1994-03-01
影响因子：
11.1
通讯作者：
SATOH, N
中科院分区：
文献类型：
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作者：
WADA, H;SATOH, N
两种毛颌动物、五种棘皮动物、一种半索动物和两种尾索动物（一种幼虫和一种樽海鞘）的 18S rDNA 几乎全部序列均已确定。这些序列与其他后口动物（海鞘、头索动物和脊椎动物）和原口动物（节肢动物和软体动物）的系统发育比较表明，除毛颌动物外，后口动物是单系的。毛颌动物可能不是一组后口动物。最接近脊椎动物的后口动物群是头索动物群。海鞘类、幼体类和樽海鞘类似乎形成一个独立的类群（尾索类），其中幼体类的早期分化是明显的。这些结果支持了脊索动物从自由生活的祖先进化而来的假设。
Almost the entire sequences of 18S rDNA were determined for two chaetognaths, five echinoderms, a hemichordate, and two urochordates (a larvacean and a salp). Phylogenetic comparisons of the sequences, together with those of other deuterostomes (an ascidian, a cephalochordate, and vertebrates) and protostomes (an arthropod and a mollusc), suggest the monophyly of the deuterostomes, with the exception of the chaetognaths. Chaetognaths may not be a group of deuterostomes. The deuterostome group closest to vertebrates was the group of cephalochordates. Ascidians, larvaceans, and salps seem to form a discrete group (urochordates), in which the early divergence of larvaceans is evident. These results support the hypothesis that chordates evolved from free-living ancestors.