Hox genes in brachiopods and priapulids and protostome evolution
Hox genes in brachiopods and priapulids and protostome evolution
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DOI：
10.1038/21631
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发表时间：
1999-06-24
期刊：
影响因子：
64.8
通讯作者：
Balavoine, G
中科院分区：
文献类型：
--
作者：
de Rosa, R;Grenier, JK;Balavoine, G
要了解动物身体计划的早期进化，既需要后生动物的系统学知识，也需要特定形式出现所涉及的遗传和发育变化的知识。最近的18S核糖体RNA系统发育研究表明，该属有三个分支，包括后口动物和两个大的原口动物分支，即Lophotrochozoans(1)和Edysozoans(2)。在这里，我们表明，在关键的原口动物门的NOR基因的补充性反映了这些系统发育关系，并揭示了双边动物发育调节潜力的早期进化。我们已经确定了原生口门各亚群共有的HOX基因。其中包括腕足类和多毛类环节动物中一对分离的后部(类似腹部的)基因，它支持Lophotrochozoa组合；以及一种独特的后部Hox基因，它由无节肢动物、线虫和节肢动物共享，它支持蜕皮动物Dade。这两个主要原生生物谱系的祖先都至少有8到10个HOX基因。因此，HOX基因扩增和多样化的主要时期出现在三大双边支系各自的辐射之前。
Understanding the early evolution of animal body plans requires knowledge both of metazoan phylogeny and of the genetic and developmental changes involved in the emergence of particular forms. Recent 18S ribosomal RNA phylogenies suggest a three-branched tree for the Bilateria comprising the deuterostomes and two great protostome clades, the lophotrochozoans(1) and ecdysozoans(2). Here, we show that the complement of Nor genes in critical protostome phyla reflects these phylogenetic relationships and reveals the early evolution of developmental regulatory potential in bilaterians. We have identified Hox genes that are shared by subsets of protostome phyla. These include a diverged pair of posterior (Abdominal-B-like) genes in both a brachiopod and a polychaete annelid, which supports the lophotrochozoan assemblage, and a distinct posterior Hox gene shared by a priapulid, a nematode and the arthropods, which supports the ecdysozoan dade. The ancestors of each of these two major protostome lineages had a minimum of eight to ten Hox genes. The major period of Hox gene expansion and diversification thus occurred before the radiation of each of the three great bilaterian clades.