Genetic structure, population diversity and ancestry of Nicobari fowl based on mtDNA complete D-loop sequences

Nicobari fowl constitute an endemic poultry germplasm of Andaman and Nicobar Islands, India. Genetic diversity, population structure and ancestry of Nicobari fowl were analysed with mitochondrial D-loop sequences. Analysis of complete D-loop sequences (1231-1232 bp) showed 46 polymorphic sites resulting in 26 haplotypes with overall haplotype diversity of 0.895 and nucleotide diversity of 0.0064. Analysis of molecular variance of spatial populations (sampling sites) of Nicobari fowl revealed that the estimated F_ST value as 0.229 among the populations. Tajima's D and Fu's F_S tests indicated nonsignificant deviation from neutrality and the multimodal pattern of mismatch distribution in demographic expansion suggested that Nicobari fowl populations are in equilibrium. The median-joining (MJ) network of D-loop sequences with reference haplogroup sequences identifies the presence of haplogroups A, B, E1, E2, F and I in Nicobari fowl. The major haplogroup in Nicobari fowl was E (60%), which is otherwise found mainly in the Indian subcontinent. Phylogenetic analysis of Nicobari fowl with junglefowl by maximum likelihood method showed Gallus gallus murghi and G. g. spadiceus as maternal progenitors. Grouping of Nicobari fowl with their primary ancestor, Indian red Junglefowl (G. g. murghi) and the presence of Indian subcontinent-specific haplogroups (E2 and I) support the independent domestication of chickens in India. This study will help to design breeding strategy for conservation of Nicobari fowl in its island habitat.