磷虾类线粒体基因组的特征和基因排列比较

Comparison of the characteristics and gene order in mitochondrial genomes of krills

中文关键词: 磷虾  长PCR  线粒体基因组  基因重排  分子标记

英文关键词: Krill  Long PCR  Mitochondrial genome  Gene rearrangement  Molecular marker

中文摘要:

      利用长PCR扩增获得太平洋磷虾的线粒体DNA，结合鸟枪法和引物步移法测定太平洋磷虾的线粒体基因组。结果表明，太平洋磷虾线粒体基因组全长为16 898 bp，在最大非编码区中存在一个串联重复区域（4.7×154 bp）。在15个主编码基因中，变异位点数最多的是nad5基因（319~321个），其次为nad4基因（284~285个）和cox1基因（232~233个）。因此，nad5基因和nad4基因可以作为候选的分子标记，用于分析磷虾类不同的物种和群体之间的生物多样性。对比泛甲壳动物的原始排列，太平洋磷虾和南极磷虾线粒体基因组共享3个转运RNA基因（tRNALeu(CUN)、tRNALeu(UUR)和tRNATrp）的易位。与太平洋磷虾线粒体基因组相比，南极磷虾线粒体基因组存在1个转运RNA基因（tRNAAsn）的重复和1个转运RNA基因（tRNAIle）的易位。太平洋磷虾和南极磷虾之间的基因排列并不完全一致，说明在磷虾类内部线粒体基因组的基因排列顺序并不保守。

英文摘要:

      The mitochondrial genomic DNA of Euphausia pacifica was obtained by long PCR amplification, and was then sequenced using shotgun and primer-walking strategies. The mitochondrial genome of E. pacifica is 16,898 bp in length. The largest non-coding region in E. pacifica mitochondrial genome contains one section with tandem repeats (4.7×154 bp). Nad5 gene has the largest number of different loci (319~321), followed by nad4 (284~285) and cox1 (232~233) gene. Therefore, nad5 and nad4 genes can be used as alternative molecular markers to analyze genetic diversity among krills species and populations. Translocation of three tRNAs (tRNALeu(CUN), tRNALeu(UUR) and tRNATrp) is shared by E. pacifica and E. superba mitochondrial genomes when compared with the pancrustacean ground pattern. The duplication of tRNAAsn and translocation of tRNAIle were found in the mitochondrial genome of E. superba when compared with the E. pacifica mitochondrial genome. Gene orders are not identical between E. pacifica and E. superba mitochondrial genomes, indicating that gene order is not conserved among euphausiids mitochondrial genomes.