The chicken (Gallus gallus) was domesticated about 5,400 years ago through purposeful breeding and extensive use of wild Jungle fowl in Southeast Asia including India. The origin and domestication of chickens has been of enormous interest to researchers and breeders as distribution of chickens have been observed through being enrouted from Asian domestication centres to the Middle East and Africa, subsequently Europe and America. Archeological evidences and other historical findings have not been able to confirm precise route of distribution of chicken breeds across the globe. The advent of modern biotechnological tools has helped us to enumerate the precise evolutionary relationship among species/breeds/clans/lines/strains etc. Of several molecular technologies, mitochondrial DNA sequence based method has been one of the most authenticated tools to analyse evolutionary perspectives among populations.
The mtDNA has been immensely important molecule to study as it is enormously associated with onset of several diseases and stress, and important cellular functions combating climate resilience. Indigenous breeds are well adapted to unfavourable climate change making the breed popular in tropical hot humid climate. India harbors 18 native breeds of chicken including Red Jungle Fowl as wild ancestor of modern chicken breeds. The whole mitochondrial sequence of six Indian native chickens, namely Aseel, Ghagus, Nicobari (Black and Brown), Tellicherry, Kadaknath and Haringhata Black have been explored through Ion PGM Sequencer and analyzed with Torrent suite v 3.6. In the chicken Mitochondrial genome, there were 37 genes encoding 13 proteins, 2 rRNAs and 22 tRNAs encompassing 16,775 bp circular DNA. The sequence variabilities among the breeds have been determined in terms of SNPs, insertion and deletion in the genome (see figure). These nucleotide variations in the mitochondrial genome can be further used for determination of genetic markers for disease and stress resilience traits, and phylogenetic relationship among chicken breeds and other animal species to commensurate domestication process in the evolutionary lineage.
Further information can be obtained at e-mail: bhattacharyatkgmail [dot] com
(Source: Directorate of Poultry Research, Hyderabad)