Mitochondrial DNA control region polymorphisms in Henan Gamecocks and evolutionary relatedness with other four Gamecock breeds
To determine the origin and genetic diversity of Henan Gamecocks, blood samples were collected from 28 chickens, and the complete mt DNA D-loop was amplified by PCR and sequenced subsequently. DNA sequences of mt DNA D-loop of four gamecock breeds were collected from the Gen Bank and used as the reference sequences. The results showed that the D-loop region of Henan Gamecocks was 1232 bp in length. The haplotype diversity was 0.542, and the nucleotide diversity was 0.00236. The 3 haplotypes were observed based on 9 mutant sites. Estimates of evolutionary divergence between breeds showed that the Henan Gamecocks was genetically closest to the Xishuangbanna Gamecocks(0.0095) and farthest to Zhangzhou Gamecocks(0.0226). Five original clades(A, B, C, D and E) were found among five gamecock breeds using a neighbor-joining phylogeny. It is concluded that the Henan Gamecocks are moderately genetically diverse and have two maternal origins. The genetic structure of Henan Gamecocks in China might be influenced by the subsequent breed selection and conservation after the initial gamecock introduction.