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.