Abstract: Cyt b and D-loop of mitochondrial DNA in Nycticebus pygmaeus (sample=7) in Daweishan Nature Reserve from Yunnan province were PCR amplification in the present study, and the sequences of Cyt b and D-loop were tested, nucleotide compositions and polymorphism were analyzed. The results showed that in the gene of Cyt b, the proportion of four nucleotides(A, T, C and G) were 29.3%, 28.2%, 29.8% and 12.7%, respectively. Content of A+T was 57.5%, and content of G+C was 42.5%. In Cyt b gene sequences (1078 bp in length ), there were 4 variable sites, π value was 0.00106, only 3 haplotypes appeared in 7 samples. Genetic distance was 0.000-0.003 in N. pygmaeus. In the gene of D-loop, the proportions of four nucleotides(A, T, C and G) were 31.8%, 29.1%, 25.0% and 14.1%, respectively. Content of A+T was 60.9%, and content of G+C was 39.1%. In D-loop gene sequences (381 bp in length), there were 4 variable sites, π value was 0.00300, only 4 haplotypes appeared. Genetic distance was 0.000-0.003 in N. pygmaeus. All of the results suggested that litter differences existed between individuals within species, and had low levels of polymorphism in groups. Compared with other species, through the analysis of genetic diversity, N. pygmaeus showed lower hereditary and population numbers, genetic drift occured larger. Therefore, it was eager to protect the N. pygmaeus on the level of genetic diversity.

Key words: Nycticebus pygmaeus, Cyt b, D-loop