Reconstruction of phylogenetic relationships of korean chickens using mitochondrial d-loop sequences

Two hypotheses of monophyletic and multiple origins have been documented for chicken domestication. The maternally inherited D-loop region in mtDNA is widely used for the investigation of relationships between populations and individuals of various animal species. In this study, 854 Korean chicken mtDNA D-loop sequences were investigated. Thirty five nucleotide substitutions were identified from the sequence analyses, and they were classified as twenty eight haplotypes. Phylogenetic analyses revealed five divergent mtDNA clades (A to E) based on geographical distribution. There was no breed specific clade among the Korean chickens. Moreover, the estimation of network profiles was traced using 28 haplotypes and five mtDNA clades. Korean chickens were discriminated based on the nucleotide positions. The clades A, B, and E are distributed universally in Eurasia, and among them, 95.78% Korean chickens were included. On the other hand, C and D clades were represented 2.34 and 1.87% of Korean chickens, respectively. Our mtDNA results indicate that Korean chickens share mtDNA haplotypes with a number of chicken breeds from South China, Japan, Europe, Middle East and Indian subcontinent regions. Therefore, the results suggest that Korean chickens have multiple maternal origins.