Torricelli Giulia, Carapelli Antonio, Convey Peter, Nardi Francesco, Boore Jeffrey L, Frati Francesco
Department of Evolutionary Biology, University of Siena, 53100 Siena, Italy.
Gene. 2010 Jan 1;449(1-2):30-40. doi: 10.1016/j.gene.2009.09.006. Epub 2009 Sep 25.
Collembola are one of the few hexapod groups adapted to live in the harsh environmental conditions of Antarctic terrestrial ecosystems. Diversity is limited to a few species that can be very abundant in coastal deglaciated sites. A remarkable lack of overlap in Collembola species composition is evident between Western and Eastern Antarctica, and Friesea grisea is currently the only species whose distribution is thought to span these two main regions of the continent. However, our analysis of the complete sequences of the mitochondrial genomes from specimens obtained from each of the two regions showed unexpected genetic divergence, well above the average levels observed between populations belonging to the same species, and so indicating that these are actually separate species, despite their lack of distinguishing morphology. Detailed analysis of the two genomes showed the presence of a non-coding region observed between trnS(uga) and nad1. Other features of these mitochondrial genomes, such as base compositional bias, secondary structure features of tRNAs and the presence of regulatory elements in the control region, are described and discussed from an evolutionary standpoint.
弹尾目昆虫是少数适应生活在南极陆地生态系统恶劣环境条件下的六足动物类群之一。其多样性仅限于少数几种，这些种类在沿海冰消区可能数量众多。在南极西部和东部之间，弹尾目昆虫的物种组成明显缺乏重叠，而灰色弗氏弹尾虫是目前唯一一种分布被认为跨越该大陆这两个主要区域的物种。然而，我们对从这两个区域获取的标本的线粒体基因组完整序列进行分析后发现，存在意想不到的遗传差异，远高于同一物种不同种群之间观察到的平均水平，这表明尽管它们缺乏明显的形态差异，但实际上是不同的物种。对这两个基因组的详细分析表明，在trnS(uga)和nad1之间存在一个非编码区。从进化的角度对这些线粒体基因组的其他特征，如碱基组成偏差、tRNA的二级结构特征以及控制区调控元件的存在进行了描述和讨论。
