Danzhou chicken: a unique genetic resource revealed by genome-wide resequencing data

Danzhou chicken (DZ) is a local breed in China noted for its strong adaptability, roughage resistance, strong wildness, and delicious taste, thus containing important genetic resources. In this study, genome re-sequencing data was generated from 200 DZ chickens. Combined with previously generated data from 72 additional chickens across six other exotic and local breeds, these data were used to systematically evaluate the germplasm characteristics of DZ chickens from a genomic perspective. Unlike exotic breeds, both DZ and southern local chicken varieties exhibited high genetic diversity, and the genetic distance between DZ and southern local chickens was smaller than the genetic distance between DZ and exotic chickens. A reconstructed Neighbor-Joining phylogenetic tree indicated that all sampled populations clustered into single independent populations, with DZ chickens showing clear evidence of intra-population differentiation, forming 2 subpopulations. Principal component analysis and ADMIXTURE analysis showed that DZ was significantly different from other breeds. These results indicate that DZ is a unique genetic resource that is different from other southern native and exotic chickens. The results of the study will improve our understanding of the genetic structure and current status of the DZ breed, which is of great significance in promoting the conservation of genetic resources of DZ chickens and fostering breed innovations and genetic improvement.