Institute of Biology II: Zoologie, Molekulare Evolution und Systematik der Tiere, University of Leipzig, Leipzig, Germany.
Mol Phylogenet Evol. 2010 Jul;56(1):201-11. doi: 10.1016/j.ympev.2010.01.035. Epub 2010 Feb 10.
The genome architecture and amino acid sequences of six new complete mitochondrial genomes were determined from representatives of Hemichordata (1), Ophiuroidea (3), Echinoidea (1) and Holothuroidea (1) and were analysed together with previously known sequences. Phylogenetic analyses recovered three lineages within echinoderms, Crinoidea, Ophiuroidea and a group comprising Holothuroidea, Echinoidea, and Asteroidea. In contrast to previous analyses of mitochondrial genomes the increased data set recovered the classical echinoderm phylogeny of Eleutherozoa and Echinozoa in Maximum Likelihood and Bayesian analyses using hemichordate out-group representatives. However, an inconsistent ramification appeared with vertebrate out-groups and in Maximum Parsimony and Neighbour Joining reconstructions. The basal (consensus) gene orders of all three lineages could be derived from a hypothetical ancestral crinoid gene order by one single rearrangement in each lineage. The genome architecture was highly conserved in Echinoidea, whereas the highest gene order differences and large amounts of unassigned sequences (UAS) were detected in Ophiuroidea, supporting a higher evolutionary rate than in any other echinoderm lineage. The variability in gene order and UAS regions in ophiuroid genomes suggest dominating rearrangement mechanisms by duplication events.
从半索动物（1）、蛇尾纲（3）、海胆纲（1）和海参纲（1）的代表中确定了六个新的完整线粒体基因组的基因组结构和氨基酸序列，并与以前已知的序列一起进行了分析。系统发育分析在棘皮动物中恢复了三个谱系，即海百合纲、蛇尾纲和包括海参纲、海胆纲和海星纲的一个群体。与以前对线粒体基因组的分析相比，增加的数据集在使用半索动物外群代表的最大似然和贝叶斯分析中恢复了经典的棘皮动物进化枝 Eleutherozoa 和 Echinozoa。然而，在外群和最大简约法以及邻接法重建中出现了不一致的分支。所有三个谱系的基本（共识）基因顺序都可以通过每个谱系中的一次单一重排从假设的原始海百合基因顺序推导出来。棘皮动物的基因组结构高度保守，而蛇尾纲的基因顺序差异最大，未分配序列（UAS）数量最多，支持比任何其他棘皮动物谱系更高的进化速度。蛇尾纲基因组中基因顺序和 UAS 区域的可变性表明存在主导的重排机制，即通过复制事件。
