猫蛱蝶线粒体基因组全序列分析

ANALYSIS OF COMPLETE MITOCHONDRIAL GENOME OF TIMELAEA MACULATA (LEPIDOPTERA,NYMPHALIDA)

采用PCR步移法对猫蛱蝶Timelaea maculata线粒体基因组全序列进行了测定和分析。分析结果表明:猫蛱蝶线粒体基因组全长15178bp,包括13个蛋白编码基因、22个tRNA基因、2个rRNA基因和一段长度为382bp的A+T富含区,基因排列顺序与其它已知鳞翅目昆虫相同。猫蛱蝶线粒体基因组中存在很高的A+T含量(81.1%)。13个蛋白编码基因中除COⅠ以CGA作为起始密码外,其余蛋白质基因均以ATN作为起始密码子。COⅡ和ND4基因使用了不完全终止密码子T,其余基因均以典型的TAA、TAG为终止密码子。在所测得的22个tRNA基因中,除tRNASer(AGN)缺少DHU臂外,其余tRNA均能形成典型的三叶草结构。与其它多数鳞翅目昆虫一样,猫蛱蝶的A+T富含区中有一段由"ATAGAA"引导的保守的多聚T结构,长度为19bp,并散在着一些长短不一的串联重复单元。

The complete mitochondrial genome of Timelaea maculata w as determined and analyzed by using polymerase chain reaction amplification and prime w alking. The results indicates that the complete mitochondrial genome of T. maculata is a circular molecule of 15 178 nucleotides,including 13 protein-coding genes,22 tRNA genes,2 rRNA genes and 382 bp A ＋ T-rich region. The arrangement of genes in T. maculata is consistent w ith the sequence of other sequenced lepidopteran species. The mitochondrial genome of T. maculata is biased tow ard a high A＋Tcontent （A＋T=81.1%） . Except the initiationcodons of COⅠ gene is a CGA codon,the other protein coding genes start with a typical ATN codon. Majority of the 13 PC Gs in T. maculata have a complete termination codon （TAA、TAG） ,except for the termination codons in COⅡ and ND4 that had an incomplete T. All tRNAs show the classic clover-leaf structure,except that the dihydrouridine （DHU） arm of tRNA Ser（AGN） forms a simple loop. Compared to the other related species,the A ＋ T-riched region of T. maculata contains the motif ＂ATAGAA＂ and 19 bp poly-Tstretch,and different tandem repeat units.