蒙古狼线粒体基因组序列分析及其系统发育地位

The mitochondrial genome of the Mongolian wolf Canis lupus chanco and a phylogenetic analysis of Canis

应用Long-PCR和克隆测序法得到蒙古狼(Canis lupus chanco)线粒体基因组全序列,结合GenBank中现有犬科动物线粒体基因组数据,应用最大简约法(MP)、最大似然法(ML)和Bayesian分析法对蒙古狼的系统发育地位进行了探讨。结果如下:蒙古狼线粒体基因组全长16709bp,包含13个蛋白质编码基因、22个tRNA基因、2个rRNA基因和1个非编码区。序列碱基的组成存在明显的A-T偏好性。tRNA基因中除tRNA-Ser(AGY)缺少双氢尿嘧啶(DHU)臂以外,其余均能折叠成典型的三叶草二级结构。大多数蛋白质编码基因的起始和终止密码子与犬科动物有报道相同,COXⅡ基因的起始密码子为ATA,与其他犬科动物不同。基于12S rRNA+16S rRNA+H链上的12个蛋白质编码基因的联合数据的系统发育分析发现,在已报道的狼亚种数据中,西藏狼(Canis lupus laniger)的分化时间最早,其次为阿拉伯狼(Canis lupus arabs),蒙古狼与欧亚狼(Canis lupuslupus)的系统发育地位最为接近。

The complete mitochondrial genome sequence of the Mongolian wolf,Canis lupus chanco,was determined by the long and accurate polymerase chain reaction （ L-PCR） based on the PCR fragments of primers. In order to clarify the phylogenetic position of Canis lupus chanco,we constructed the phylogenetic tree based on the concatenated 12S rRNA ＋ 16S rRNA ＋ 12 heavy-strand protein-coding genes of 12 Canidae animals with the genomic data obtained from GenBank. Here are the results：The entire mtDNA sequence is 16709 base pairs （bp） in length and contains two ribosomal RNA genes,13 protein-coding genes,22 transfer RNA genes and one control region. A strong A-T bias was found in the nucleotide sequence of mitochondrial genome of the Mongolian wolf. All the transfer RNA genes could be folded into the typical cloverleaf-shaped structure except tRNA-Ser （AGY）,which lacked the ＂DHU＂ arm. Most of the protein-coding genes have the same codon usage as other Canidae animals except COX Ⅱ gene,which terminates with the stop codon ATA. The phylogenetic analysis indicated that within the subspecies data of Canis lupus,Canis lupus laniger polarized first,then did Canis lupus arabs. Canis lupus chanco and Canis lupus lupus were sister species,which had similar phylogenetic positions.