| The Asiatic black bear (Selenarctos thibetanus) is in the family Ursidae (Carnivora). It distributes in Russia, India, Nippon, Japan, Korea, Afghanistan, Pakistan, and China. In the 1980s, the hot breeding come from cholerrhagia of living black bear resulted in approximately 9000 wild-lives being imprisoned in China. As limited by breeding conditions, the imprisoned black bears have only one-third life span compared with the wild-ones. So the amounts of Asiatic black bears reduced obviously. The protected status of the Asiatic black bear is in the Convention on International Trade in Endangered Species (CITES) Appendix I, and it also get into endangered red book (easily endangered V) in our country now. The Asiatic black bear have higher economical value and is the relative to giant panda. As it is difficult to gain materials, the domestic researches have focued mainly on morphology, feeding, breeding and cholerrhagia et al;the international researches concentrate on infectious diseases, morphology, behavior biology, all kinds of diseases and growth and development and so on till now. It is rare of the reports about karyotype analysis and genetic structure;the study on molecular level only being doing on several mitochondrial DNA, has no reports about nuclear gene. In order to satisfy the needs of feeding and using reasonably, it is indispensable to gather information about black bear on molecular level and discuss the relationship between black bear and other bears, provide evidence for black bears ecology, genetics, breeding and development.Using our lab's improved protocol for faecal DNA extraction, the entire 753-bp DNA coding sequence of the nuclear brain-derived neurotrophic factor (BDNF) gene was cloned for the first time from Asiatic Black Bear (Selenarctos thibetanus) faecal samples with primers based on the reported sequence of the Malayan Bear BDNF gene. Hair was used as a positive control and the experiments were repeated several times to obtain reliable and identical results. Sequence analysis showed that the BDNF gene of Asiatic Black Bear was highly conserved compared to those of human and giant panda, with an identity of 94.5% and 98.9%, respectively. The deduced amino acid sequence ofthe mature protein was found to be identical to those of all the reported mammalians. According to gene sequence alignment, the giant panda appeared to be phylogenetically closer to Asiatic Black Bear than the lesser panda. This study represents the first time that a non-invasive method such as faecal sampling was used to analyze a functional nuclear BDNF gene of Asiatic Black Bear. It will not only provide important reference for the conservation and breeding of Asiatic Black Bear and open up new avenues of non-invasive sampling in the study of endangered wildlife, but also provide another molecular evidence for the study of relationship of Asiatic Black Bear and its related species.The 357-bp DNA coding sequence of the nuclear Actviin fiA subunit gene was cloned for the first time from Asiatic Black Bear (Selenarctos thibetanus) faecal and hair samples with degenerate primers based on the reported sequence of other species Activin fiA subunit gene. Water was used as a negative control and the experiments were repeated several times to obtain reliable and identical results. Sequence analysis showed that the Activin fiA subunit gene of Asiatic Black Bear was highly conserved compared to other species that have different evolution levels, with an identity of 91.6% to human (29-bp changes). There have 4, 20, 3 base pairs changes separately compared to giant panda (Ailuropoda melanoleuca), lesser panda (Ailurus fulgens) and sun bear (Helarctos malayanus), with identities of 98.9%, 94.4%, 99.2% respectively. Analysis of phylogenisis and cleavage site, the Asiatic black bear, giant panda and sun bear appeared to be phylogenetically closer but all have a remote relationship with the lesser panda.
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