Komiya K, Kondoh T, Aotsuka T
Department of Biology, Tokyo Metropolitan University, Japan.
Biochem Genet. 1995 Apr;33(3-4):73-82. doi: 10.1007/BF00557945.
The sequences of the mitochondrial DNA (mtDNA) segment containing the two intergenic regions were determined for six species belonging to the Drosophila immigrans species group and compared to the corresponding segments of Drosophila species which had been studied previously. We found remarkable differences in the evolutionary rates of the two intergenic regions. The Intergenic I region, which lies between the tRNA(gln) and the tRNA(ile) genes, was found to be highly conserved in terms of both size (30 ntp) and nucleotide sequence among the species studied. In contrast, the sequences of the Intergenic II region, which lies between the tRNA(f-met) and the tRNA(ile) genes, showed considerable variation. The size of the Intergenic II region ranged from 0 to 88 ntp, and accurate alignment was possible only among sequences from geographical strains or very closely related species in the nasuta species subgroup. The observed differences in conservation of the two mtDNA intergenic regions are discussed in light of functional constraints on mtDNA sequences.
测定了果蝇迁入种组六个物种中包含两个基因间隔区的线粒体DNA（mtDNA）片段序列，并与之前研究过的果蝇物种的相应片段进行了比较。我们发现这两个基因间隔区的进化速率存在显著差异。基因间隔区I位于tRNA（谷氨酰胺）和tRNA（异亮氨酸）基因之间，在所研究的物种中，其大小（30个核苷酸）和核苷酸序列方面都高度保守。相比之下，位于tRNA（甲硫氨酸）和tRNA（异亮氨酸）基因之间的基因间隔区II的序列表现出相当大的变异。基因间隔区II的大小范围为0至88个核苷酸，只有在来自地理菌株或纳苏塔物种亚组中非常密切相关物种的序列之间才能进行准确比对。根据对mtDNA序列的功能限制，讨论了观察到的两个mtDNA基因间隔区保守性的差异。
