Hemocyanin Suggests a Close Relationship of Remipedia and Hexapoda
Hemocyanin Suggests a Close Relationship of Remipedia and Hexapoda
复制标题
DOI：
10.1093/molbev/msp186
复制
发表时间：
2009-12-01
影响因子：
10.7
通讯作者：
Burmester, Thorsten
中科院分区：
文献类型：
--
作者：
Ertas, Beyhan;von Reumont, Bjoern M.;Burmester, Thorsten
Remipedia是一种神秘的甲壳类动物，来自安基亚林洞穴系统，30年前首次被描述，其系统发育亲缘关系尚未解决。本文报道了1987年沙蛭科（蛭科）血青素的序列。这是甲壳类动物中除马拉斯甲外首次发现这种呼吸蛋白的证据。血青素由多个不同的（至少三个）亚基（StuHc1-3; Hc，血青素）组成。令人惊讶的是，这些序列与六足动物的血青素最为相似。系统发育分析表明，图卢马血青素亚基StuHc1和StuHc3与六足动物的1型血青素亚基相关，而StuHc2与六足动物的2型血青素亚基相关。两足动物和六足动物的血青素与马拉孔甲壳类动物的血青素同属姊妹类。血青素没有显示多足类和六足类的密切关系，但支持泛足类（甲壳类+六足类）。我们的研究结果还表明，甲壳类动物是副纲动物，六足类动物可能是从一种类似雷米亚目动物的祖先进化而来的。因此，Remipedia在了解六足动物的进化方面占据了关键地位，六足动物是世界上物种最多的动物之一。
The Remipedia are enigmatic crustaceans from anchialine cave systems, first described only 30 years ago, whose phylogenetic affinities are as yet unresolved. Here we report the sequence of hemocyanin from Speleonectes tulumensis Yager, 1987 (Remipedia, Speleonectidae). This is the first proof of the presence of this type of respiratory protein in a crustacean taxon other than Malacostraca. Speleonectes tulumensis hemocyanin consists of multiple distinct (at least three) subunits (StuHc1-3; Hc, hemocyanin). Surprisingly, the sequences are most similar to hexapod hemocyanins. Phylogenetic analyses showed that the S. tulumensis hemocyanin subunits StuHc1 and StuHc3 associate with the type 1 hexapod hemocyanin subunits, whereas StuHc2 associates with the type 2 subunits of hexapods. Together, remipede and hexapod hemocyanins are in the sister-group position to the hemocyanins of malacostracan crustaceans. Hemocyanins provide no indication of a close relationship of Myriapoda and Hexapoda but support Pancrustacea (Crustacea + Hexapoda). Our results also suggest that Crustacea are paraphyletic and that Hexapoda may have evolved from a Remipedia-like ancestor. Thus, Remipedia occupy a key position for the understanding of the evolution of hexapods, which are and have been one of the world's most speciose lineage of animals.