Bleidorn Christoph, Podsiadlowski Lars, Bartolomaeus Thomas
Free University Berlin, Institute for Biology, Zoology, Animal Systematics and Evolution, Koenigin-Luise-Str. 1-3, D-14195 Berlin, Germany.
Gene. 2006 Mar 29;370:96-103. doi: 10.1016/j.gene.2005.11.018. Epub 2006 Jan 31.
Relationships of annelid subtaxa are controversially discussed and additional markers are necessarily needed to get further insights into their evolution. Due to their high content of information, mitochondrial genomes have been proven very useful in phylogenetic analyses. Whereas many complete mitochondrial genomes of arthropods are available, lophotrochozoan taxa are only scarcely represented and this is especially true for annelids. Here we present the complete mitochondrial genome of the orbiniid polychaete Orbinia latreillii. The circular genome is 15,558 bp in size and contains the same 37 genes as found in most other metazoans. As in the case for all studied annelids all genes are transcribed from the same strand. Compared with the known data from other annelids at least five gene translocations must be hypothesized for O. latreillii. A comparison of the available data shows that gene translocations within Annelida seem to be less frequent than in molluscs, but more frequent as previously assumed. Phylogenetic analyses of mitochondrial DNA sequence data and amino acid data support an inclusion of Sipuncula within Annelida and a closer relationship to orbiniids is recovered for this taxon.
环节动物亚类群之间的关系存在争议，需要更多标记以深入了解其进化过程。线粒体基因组因信息含量高，已被证明在系统发育分析中非常有用。节肢动物有许多完整的线粒体基因组，而触手冠动物类群的代表却很少，环节动物尤为如此。在此，我们展示了多毛纲仙女虫科的拉氏仙女虫（Orbinia latreillii）的完整线粒体基因组。该环状基因组大小为15,558 bp，包含与大多数其他后生动物相同的37个基因。与所有已研究的环节动物一样，所有基因都从同一条链转录。与其他环节动物的已知数据相比，拉氏仙女虫至少有五个基因易位。现有数据比较表明，环节动物内的基因易位似乎比软体动物中少见，但比之前认为的更频繁。线粒体DNA序列数据和氨基酸数据的系统发育分析支持星虫动物门归入环节动物门，且该类群与仙女虫科关系更近。
