Cloning and sequence analysis of mtDNA cytochrome c oxidase subunitⅠ gene of the Asian Black Bear Sichuan Subspecies / 第三军医大学学报

ABSTRACT

Objective To explore the features of the cytochrome c oxidase subunit Ⅰ (COXⅠ) of Asian black bear Sichuan subspecies. Methods Primers were designed according published gene sequences of other bear species. A DNA sequence was amplified by PCR from the bear Sichuan subspecies’s hair-follicle tissue total DNA, then the PCR product was sequenced. The results were analyzed and a forecast analysis was carried on. Results The amplified COXⅠ gene of Sichuan black bear was 1 605 bp and contained a 1545-nucleotide open reading frame encoding 514 amino acid residues. The overall base composition of COXⅠ gene is 26.9 %, 23.1%, 18.3 %, and 31.8 % respectively to A, C, G, and T. The start codon of the COXⅠ is ATG, while the termination codon TAA. The protein’s pI is 6.29 and weight is 57.2?10 3 . The similarity analysis and phylogenetic tree analysis indicated that Sichuan black bear has closer relationship to American black bear, but not to brown bear and polar bear. Among dogs, caws and rats, it is closer to the former one. Conclusion There are high similarities in the DNA sequence, protein amino acid sequence of Asian black bear Sichuan subspecies with other bear species, indicating a high conservativity of COXⅠ in these involved species.