Evolution of duplicate control regions in the mitochondrial genomes of metazoa:: A case study with Australasian Ixodes ticks
Evolution of duplicate control regions in the mitochondrial genomes of metazoa:: A case study with Australasian Ixodes ticks
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DOI：
10.1093/molbev/msi047
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发表时间：
2005-03-01
影响因子：
10.7
通讯作者：
Fukunaga, M
中科院分区：
文献类型：
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作者：
Shao, RF;Barker, SC;Fukunaga, M
为了研究线粒体（mt）基因组中重复控制区（CR）的进化模式和系统发育效用，我们对三种硬蜱的全部mt基因组和另一种硬蜱的部分mt基因组进行了测序。所有来自澳大拉西亚血统的物种都有重复的CR，而其他物种只有一个CR。序列分析表明，这两个CRs的澳大利亚硬蜱在每个物种的音乐会。除了澳大利亚硬蜱外，其他7个后生动物谱系的物种也具有带有重复CR的mt基因组。从这些后生动物和两个最近的实验复制的mt基因组在人类细胞系的重复CRs积累的mtDNA序列数据，使我们能够重新审视四个有趣的问题，重复CRs在后生动物的mt基因组中的存在：（1）为什么有些mt基因组，而不是其他人，有重复的CRs？(2)带有重复CRs的mt基因组是如何进化的？(3)在进化过程中，重复CRs的核苷酸序列如何保持相同或非常相似？(4)重复的CR是系统发育标记吗？与具有一个CR的mt基因组相比，具有重复CR的mt基因组在复制方面具有选择性优势。串联重复后基因缺失是产生具有重复CR的mt基因组的最合理机制。一旦在mt基因组中出现重复的CR，它们往往会协同进化，可能是通过基因转换。然而，有些谱系中的基因转换可能并不总是发生，因此，这两个CR可能在这些谱系中独立进化。重复CRs在低分类学水平（如属内、科内或科间）有很大的潜力作为系统发育标记，但在高分类学水平（如目间）则没有潜力。
To investigate the evolution pattern and phylogenetic utility of duplicate control regions (CRs) in mitochondrial (mt) genomes, we sequenced the entire mt genomes of three Ixodes species and part of the mt genomes of another I I species. All the species from the Australasian lineage have duplicate CRs, whereas the other species have one CR. Sequence analyses indicate that the two CRs of the Australasian Ixodes ticks have evolved in concert in each species. In addition to the Australasian Ixodes ticks, species from seven other lineages of metazoa also have mt genomes with duplicate CRs. Accumulated mtDNA sequence data from these metazoans and two recent experiments on replication of mt genomes in human cell lines with duplicate CRs allowed us to re-examine four intriguing questions about the presence of duplicate CRs in the mt genomes of metazoa: (1) Why do some mt genomes, but not others, have duplicate CRs? (2) How did mt genomes with duplicate CRs evolve? (3) How could the nucleotide sequences of duplicate CRs remain identical or very similar over evolutionary time? (4) Are duplicate CRs phylogenetic markers? It appears that mt genomes with duplicate CRs have a selective advantage in replication over mt genomes with one CR. Tandem duplication followed by deletion of genes is the most plausible mechanism for the generation of mt genomes with duplicate CRs. Once duplicate CRs occur in an mt genome, they tend to evolve in concert, probably by gene conversion. However, there are lineages where gene conversion may not always occur, and, thus, the two CRs may evolve independently in these lineages. Duplicate CRs have much potential as phylogenetic markers at low taxonomic levels, such as within genera, within families, or among families, but not at high taxonomic levels, such as among orders.