Tandem duplication of mitochondrial DNA in the black-faced spoonbill, Platalea minor
Tandem duplication of mitochondrial DNA in the black-faced spoonbill, Platalea minor
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DOI：
10.1266/ggs.84.297
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发表时间：
2009-08-01
影响因子：
1.1
通讯作者：
Koike, Hiroko
中科院分区：
文献类型：
--
作者：
Cho, Hyong-Ju;Eda, Masaki;Koike, Hiroko
用LA-PCR法研究了黑脸琵鹭控制区(CR)的线粒体(Mt)异质性。为了避免mtDNA转座核基因组片段(Numt)的扩增，使用针对COIII基因的退火性设计的引物来扩增几乎完整的线粒体基因组的PCR产物。然后以几乎完整的线粒体基因组聚合酶链式反应产物为模板，在细胞色素b和12S rRNA基因之间扩增出嵌套式LA-PCR产物。核苷酸序列分析显示串联重复由两个单位组成。前者包括Cyt b-1、tRNAT(Thr)-1、tRNA(Pro)-1、ND6-1、tRNA(Glu)-1和CR1；后者由Cyt b-2、tRNA(Thr)-2、tRNA(Pro)-2、ND6-2、tRNA(Glu)-2和CR2组成，其次是tRNA(Phe)和12S rRNA。复制的Cyt b-2序列与Cyt b-1 3‘端的499个碱基一致。除了CR外，重复序列中的其他基因与原始相应基因相同。尽管CR1和CR2都含有功能块，如结构域I中的聚C位点、鹅发夹和TAS结构，但CR1的3‘端紧随其后的是112bp的序列(非编码区)，这在CR2中或类似基因的序列同源性分析中都没有发现。同时，CR2以一个复杂的重复序列结束。两个CRS结构域I中的5‘端印花区(A区)和结构域I中的3’端印花区(B区)的进化方式截然不同：A区在同一个体中CR1和CR2之间高度变异，而B区在它们之间几乎相同，这表明协同进化。
Mitochondrial (mt) heteroplasmy in the control region (CR) of the black-faced spoonbill was investigated using LA-PCR. To avoid amplification of transpositioned nuclear genome fragment from mtDNA (numt), PCR product of the almost-complete mitochondrial genome was amplified using primers designed to anneal on the COIII gene. Then nested LA-PCR product was amplified between the cyt b and 12S rRNA genes using the almost-complete mitochondrial genome PCR product as a template. Nucleotide sequencing revealed tandem duplication composed of two units. The first contains cyt b-1, tRNAT(Thr)-1, tRNA(Pro)-1, ND6-1, tRNA(Glu)-1 and CR1, and the second consists of cyt b-2, tRNA(Thr)-2, tRNA(Pro)-2, ND6-2, tRNA(Glu)-2 and CR2, followed by tRNA(Phe) and 12S rRNA. The duplicated cyt b-2 sequence coincided with 499 bp at the 3' end of cyt b-1. With the exception of the CR, the other genes in the duplicated sequence were identical to the original corresponding gene. Even though both CR1 and CR2 contain functional blocks, such as a poly-C site, a goose hairpin and a TAS structure in Domain I, the 3' end of CR1 was followed by a 112 bp sequence (non-coding region) that was not found in CR2 or in sequence homology analysis of similar genes. Meanwhile, CR2 ended in a complicated repeat sequence. The 5' franking region in the Domain I (Region A) and the 3' franking region in the Domain I (Region B) of the two CRs evolve in quite different manners: Region A was highly variable between CR1 and CR2 in the same individuals, while Region B was almost identical between them, which indicates concerted evolution.