Comparative evolutionary analysis of rDNA ITS regions in Drosophila.
Comparative evolutionary analysis of rDNA ITS regions in Drosophila.
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DOI：
10.1093/oxfordjournals.molbev.a040131
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发表时间：
1994-05
影响因子：
10.7
通讯作者：
Christian Schliitterer;M. Hauser;A. Haeseler;D. Tautz
中科院分区：
文献类型：
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作者：
Christian Schliitterer;M. Hauser;A. Haeseler;D. Tautz
核糖体DNA的内转录间隔区（ITS）通常被认为是低功能的限制，因此它通常被视为典型的非功能间隔区序列。我们分析了黑腹果蝇亚组的五种果蝇的ITS区，这一亚组以外的两种果蝇（D。pseudoobscura和D. virilis），以及来自更远的双翅目苍蝇Musca arteritica。序列比较显示出独特的保守/趋异模式，表明某些区域比其他区域更保守。此外，二级结构计算表明ITS区域内的几个保守的结构元件。另一方面，一个统计测试，使我们能够估计分数的网站，不受选择性约束表明，超过一半的间隔区显然是自由发散和进化的速度是接近中性的序列进化速度在果蝇。ITS序列可用于推导所研究物种的分子遗传学。我们发现，ITS树在很大程度上符合迄今已知的这组物种的亲缘关系，有一个区别。D. melanogaster亚组为D. yakuba，而不是D.奥雷纳，这是通常假设的。
The internal transcribed spacer (ITS) of the ribosomal DNA is generally considered to be under low functional constraint, and it is therefore often treated as a typical nonfunctional spacer sequence. We have analyzed the ITS regions of five species from the Drosophila melanogaster subgroup, two Drosophila species from outside this group (D. pseudoobscura and D. virilis), as well as from the more distantly related dipteran fly Musca domestica. The sequence comparisons show a distinctive conservation/divergence pattern, indicating that some regions are more conserved than others. Moreover, secondary-structure calculations indicate several conserved structural elements within the ITS regions. On the other hand, a statistical test that allows us to estimate the fraction of sites that are not under selective constraint suggests that more than half of the spacer is apparently free to diverge and evolves with a rate that is close to the neutral rate of sequence evolution in Drosophila. The ITS sequences can be used to derive a molecular phylogeny for the species under study. We find that the ITS tree is largely in line with the so-far-known phylogeny of this group of species, with one difference. The species most distant within the D. melanogaster subgroup is D. yakuba, rather than D. orena, as is normally assumed.