LAUSR

Blue-crowned laughingthrush (Garrluax courtoisi), an endemic species in China, is a critically endangered and sexually monomorphic bird. It is difficult to identify the gender of this species through the observation of its external morphology. To solve this problem, we herein established a CHD1-based PCR method for sex-typing of Garrluax courtoisi. We first collected blood samples from six Bluecrowned laughingthrush raised in Nanchang Zoo, and then extracted high-quality genomic DNA from blood clots using an optimized phenol/chloroform method. We designed a degenerate primer pair to amplify fragments of the CHD1 gene, resulting an amplicon of 700 bp for males and an extra PCR product of 600 bp for females. We also performed extensive behavioral observations of these six birds and the obtained data allowed us to deduce the sexes of these birds. The sex-typing results are generally consistent with the behavior-deduced results. This study sheds light on the sex determination of other endangered birds, and also paves a road to further test the reproduction mechanism, taxonomic classification and population relationships of Garrluax courtoisi.