A PCR-based Method For The Sex Identification Of Blue-crowned Laughingthrush (Garrularx Courtoisi)

Blue-crowned laughingthrush(BCLT)is a critically endangered bird and an endemic species in China.It was originally distributed in Simao,Yunnan and Wuyuan,Jiangxi.Currently,the wild population of BCLT exits only in Wuyuan with a population size of approximate 300.During 1980's and 1990's,BCLT were exported to Hong Kong,Europe and North America through wildlife trade.Presently,there are more than 200 individuals in zoos or feeding units around the world including Nanchang Zoo.However,as a sexually monomorphic species,it's hardly to determine their sex by body,voice or behavior.In this study,genomic DNA was extracted from blood samples of six BCLTs raised in Nanchang Zoo using an optimized phenol/chloroform method.The results of agrose gel electrophoresis and spectrometer analysis show that high-quality genomic DNA was isolated with 50 ?l tissue lysis buffer,10 ?l proteinase K and a digestion time of 8 h.A sex-specific primer pair was designed based on the sequence of the CHD gene.This primer pair was successfully used to determine the sexes of these six BCLTs via a routine PCR method.The results shed insight into the sex determination of other endangered birds,and also pave a road to further test the reproduction mechanism,toxa classification and population relationships of this species.