863 genomes reveal the origin and domestication of chicken

Abstract

Despite the substantial role chickens have played in human societies across the world, both the geographic and temporal origins of their domestication remain controversial. To address this issue, we analyzed 863 genomes from a worldwide sampling of chickens and representatives of every subspecies and species of wild junglefowls. Our study suggests that domestic chickens were initially derived from a single Red Junglefowl subspecies of Gallus gallus spadiceus whose present-day range covers predominantly southwestern China, northern Thailand and Myanmar. Following their domestication, chickens were translocated across Southeast and South Asia where they interbred locally with not only other Red Junglefowl subspecies, but also other junglefowl species. SpeciXically, our results show that the most efXicient modern chicken breed, the White Leghorn, possesses a mosaic of divergent ancestries inherited from other Red Junglefowl subspecies. In addition, we identiXied a group of key genes under artiXicial selection, the most pronounced of which are involved in reproduction and/or preferentially act on regulatory regions. Lastly, we revealed that long-term selection induced excess accumulation of deleterious mutations in chicken genomes, most of which are hidden in a heterozygous state.