Cea Graciela, Gaitán-Espitia Juan Diego, Cárdenas Leyla
Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
Mol Biol Rep. 2015 Jun;42(6):1081-9. doi: 10.1007/s11033-014-3847-5. Epub 2014 Nov 30.
The edible Chilean red sea urchin, Loxechinus albus, is the only species of its genus and endemic to the Southeastern Pacific. In this study, we reconstructed the mitochondrial genome of L. albus by combining Sanger and pyrosequencing technologies. The mtDNA genome had a length of 15,737 bp and encoded the same 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes as other animal mtDNAs. The size of this mitogenome was similar to those of other Echinodermata species. Structural comparisons showed a highly conserved structure, composition, and gene order within Echinoidea and Holothuroidea, and nearly identical gene organization to that found in Asteroidea and Crinoidea, with the majority of differences explained by the inversions of some tRNA genes. Phylogenetic reconstruction supported the monophyly of Echinozoa and recovered the monophyletic relationship of Holothuroidea and Echinoidea. Within Holothuroidea, Bayesian and maximum likelihood analyses recovered a sister-group relationship between Dendrochirotacea and Aspidochirotida. Similarly within Echinoidea, these analyses revealed that L. albus was closely related to Paracentrotus lividus, both being part of a sister group to Strongylocentrotidae and Echinometridae. In addition, two major clades were found within Strongylocentrotidae. One of these clades comprised all of the representative species Strongylocentrotus and Hemicentrotus, whereas the other included species of Mesocentrotus and Pseudocentrotus.
可食用的智利红海胆（Loxechinus albus）是其属中的唯一物种，为东南太平洋地区特有。在本研究中，我们结合桑格测序和焦磷酸测序技术重建了智利红海胆的线粒体基因组。该线粒体DNA基因组长度为15,737 bp，编码与其他动物线粒体DNA相同的13个蛋白质编码基因、22个转运RNA基因和两个核糖体RNA基因。这个线粒体基因组的大小与其他棘皮动物物种的相似。结构比较表明，海胆纲和海参纲内的结构、组成和基因顺序高度保守，与海星纲和海百合纲中的基因组织几乎相同，大多数差异是由一些转运RNA基因的倒位所解释。系统发育重建支持了 Echinozoa 的单系性，并恢复了海参纲和海胆纲的单系关系。在海参纲中，贝叶斯分析和最大似然分析恢复了枝手目和盾手目的姐妹群关系。同样在海胆纲中，这些分析表明智利红海胆与地中海海胆密切相关，二者均为球海胆科和刻肋海胆科姐妹群的一部分。此外，在球海胆科中发现了两个主要分支。其中一个分支包括所有代表性物种球海胆属和半心海胆属，而另一个分支包括中球海胆属和假球海胆属的物种。
