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.

Objective To investigate the sequence characteristic of black bear's mitochondrial NADH-ubiquinone oxidoreductase chain 4 gene(ND4).Methods Primers were designed according to certain species' NADH-ubiquinone oxidoreductase ND4 in which the DNA sequence had been reported.The DNA sequence was amplified by PCR from the Asian black bear Sichuan subspecies's(Ursus thibetanus mupinensis)hair-follicle tissue total DNA and were analyzed with its amino acid sequence.Results The ND4 gene sequence length was 1 402 bp and contained a 1 377-nucleotide open reading frame encoding 459 amino acid residues.The amino acid sequence's pI was 9.37 and weight was 51.5?10 3.The DNA sequence and corresponding amino acid sequence of black bear's ND4 gene had the high similarity with those of other mammalian animals' ND4 gene,and the similarity was 89% to 91% and 94% to 95%.The result of phylogenetic tree was basically consistent with the traditional species system phylogenetic relations.Topology prediction showed the Asian black bear Sichuan subspecies's ND4 proteins contained N-glycosylation site,kinase C phosphorylation sites,casein kinase Ⅱ phosphorylation site,N-myristoylation site and leucine-rich region.In addition,black bear's ND4 protein contained leucine zipper pattern and Leucine-rich region.Conclusion The mammalia animal's ND4 gene has the high conservative nature.The pretein coded by ND4 gene has high uniformity in the function.