Sequencing D-loop of mitochondrial DNA in Tibetan mastiff and study on taxonomic status | 藏獒线粒体DNA D-loop区序列测定及其分类地位研究

中国人. 根据家犬线粒体基因组DNA序列设计引物，获得了藏獒（Tibetan mastiff）线粒体DNAD―loop区全序列，并以灰狼、郊狼作为外类群对藏獒、家犬亚种内6个大型家犬品种进行了系统发育分析。试验结果发现：藏獒线粒体DNAD―loop区序列全长1250bp．与家犬源序列的同源性为96．06％，其中有20个碱基缺失；系统发育分析发现藏獒、家犬亚种内6个大型家犬品种与灰狼聚为一大类，而郊狼自成一类，说明藏獒与其他家犬品种一样起源于灰狼，是家犬亚种内的一个品种，在分类地位上隶属于食肉目、犬科、犬属、狼种、家犬亚种；在家犬亚种内，藏獒与英国牧羊犬、兰伯格犬聚为一类，而德国牧羊犬与瑞典猎鹿犬、黑俄罗斯更犬聚在一起，再与圣伯纳犬聚为一类，从分子水平上验证了英国牧羊犬等大型犬可能含有藏獒血统的观点。[著者文摘]

英语. In this study, the primers for D-loop of Tibetan mastiff were designed according to the mitochondrial genome sequence of domestic dog, and the phylogenetic trees of Tibetan mastiff and 6 representative breeds of large breed dogs were constructed using grey wolf and eoyote as outgroups. The results showed that, the D-loop region of Tibetan mastiff was 1 250 bp, owning 96. 06% homology of the domestic dog D-loop sequence, there existed 20 bp deficiency. Phylogenetic analysis found that Tibetan mastiff, 6 domestic dog breeds and grey wolf clustered first of all, coyote clustered one group separately, indicating Tibetan mastiff and the other domestic dog originated frnm grey wolf, and Tibetan mastiff belonged to Carnivora, Canidae, Canis, C. lupus, C. lupus familiaris on animal taxonomy. In 7 domestic dogs, the Tibetan mastiff, English Shepherd and Leonberger clustered at first, German Sheepdog, Swedish Elkhound, Black Russian Terrier clustered into one group, and then clustered with Saint Bernard. This confirmed the viewpoint that many of the famous large breed dogs worldwide such as English Shepherd were possible of having blood lineage of Tibetan mastiff based on molecular data.