关键词: 羚羊亚科, 原羚属, 细胞色素b, 系统发育树

Abstract:
The phylogenetic relationships between species in genus Procapra and other genera of subfamily Antilopinae are unclear．Total DNA of Mongohan gazelle and Tibetan gazelle samples were extracted and Cyt b complete genes were sequenced(samples of the Mongolian gazelle and the Tibetan gazelle were collected from Inner Mongohan Autonomous region and Sichuan province respectively)．Through comparison between the Cyt b complete gene determined in this study and those of 31 species in the family Bovidae available from GeneBank。the sequence divergence，base composition and base subsfitufiom among these sequences were analyzed．The phylogenetic trees were constructed by most parsimonious(MP)，neighbor-joining(NJ) and maximum-likehood(ML) methods．The bootstrap values were calculated from 1 000 replicates forMP tree and NJ tree and 100 replicates for ML tree．Our study demonstrates that the Mongolian gazelle(Procapra gutturosa) and Tibetan gazelle(Procapra picticaudata) share the closest affinity and that they occupy the basal position in the Antilopinae．Procapra is monophyletic in all analyses (MP，NJ and ML trees)．The sequence divergence between Mongolian gazelle and Tibetan gazelle was 3.78％. Phylogenetic relationship between Genera of Antilopinae are more paraphyletic than monophyletic． Base on the Cyt b molecular clock (2％/million year)，the divergence time between the Mongolian and Tibetan gazelles was estimated to 1-2 million years before present and 5.7-8 million years before present between genera Procapra and others Genera of Antilopinae．

Key words: Antilopinae, Procapra, Cytochrome b, Phylogenetic tree