A study, undertaken by a Zoological Survey of India (ZSI) researcher along with three other scientists from reputed global institutes, has sought to throw light on the origin and domestication of chicken over thousands of years. The study used the largest ever whole-genome sequencing dataset of a global sampling of both domestic chickens and jungle fowl (JF) species.
It was undertaken by Mukesh Thakur of ZSI in collaboration with three other senior scientists from different global institutes.
The collaborative study did DNA sequencing of 863 genomes from four species of the genus Gallus, five sub-species of Red Jungle Fowl and various domestic chicken breeds collected worldwide.
"We obtained and sequenced 142 red jungle fowls representing all five sub species, 12 Green jungle fowls, two Grey jungle fowls and four Ceylon jungle fowls," Thakur said in a note about the paper.
"... our data, for the first time, clearly demonstrates that all five red jungle fowl subspecies are genetically differentiated from each other approximately 50,000 years ago (much earlier than chicken domestication), generally corresponding to their geographic ranges and taxonomic classifications," he said.
"Our study provides novel insights into the evolutionary history of domestic chickens and a valuable resource to facilitate the ongoing genetic and functional investigations," Thakur said.
Domestic chickens initially came from the subspecies Red Jungle Fowl (RJF)- "Gallus gallus spadiceus" with the area centred on southwestern China, northern Thailand and Myanmar, the study said.
Thakur said in his note that the study showed that following their domestication, chickens were "trans-located across South-east and South Asia where they interbred with Red Jungle Fowl sub-species and other jungle fowl species."
"The results further reveal that domestic chickens undergo genetic adaptations that underlie their unique behavioural, morphological and reproductive traits, he said.
The findings were published in Cell Research, an international journal.