马来熊的DNA序列分析与遗传多样性研究

马来熊在ＩＵＩＣＮ红皮中被列为受胁动物，其保护受到广泛的关注，本文研究了４只马来熊的线粒体ＤＮＡ序列，其中１只来自云南，其余３只产地不详，但来自不同的搜集渠道，对于每个个体，我们测定了３９７ｂｐ的细胞色素ｂ基因，３４６ｂｐ的１２ＳｒＲＮＡ基因，９８ｂｐ的ｔＲＮＡ基因和３３３ｂｐ的Ｄ环区序列，共计１１７４ｂｐ。经与黑犀牛序列比较，发现ＲＮＡ基因的空间结构对基因的进化有显著影响，环区的进化明显快于茎区

GENETIC VARIABILITY AND CONSERVATION RELEVANCE OF THE SUN BEAR AS REVEALED BY DNA SEQUENCES

Sun bear is found in Burma,Thailand, Vietnam, Sumatra, Borneo,North east of india,Malaysia, and Yunnan and Sichuan of China and has been listed in1990 IUCN Red List of Threatened Animals as a vulnerable species. In this paper,a total of1174 bases of mitochondrial DNA sequence(397 bases of cytochrome b gene,346 bases of 12SrRNA gene,98 bases of tRNA genes,and 333 bases of D-loop region) from each of four sunbears from different collections have been sequenced. Comparing with the black rhino tRNAgenes,our results suggest that the loop regions of tRNA genes evolve much fast than the stemregions.In the cytochrome b gene,12S rRNA gene and tRNA gene regions, no sequence variation among the individuals was observed, which indicates that genetic variability in the sunbear is relatively low. In the D-loop region,there are 13 and 1 sites,respectively, characterized by transition and transversion among the 4 sun bears sequenced.The relationships amongall the individuals were fully resolved based on mitochondrial D-loop sequences by using parsimony analysis. Our results suggest that the mitochondrial D-loop region is very useful for population genetic study of the sun bear.