Junglefowl ancestry and later mixing

A 2020 study comparing domestic chickens with wild junglefowl identified Gallus gallus spadiceus as the most likely initial source of domestic chickens. This red junglefowl subspecies now occurs mainly in southwestern China, northern Thailand and Myanmar. As people moved chickens through Southeast and South Asia, interbreeding contributed ancestry from other red junglefowl populations and other junglefowl species.

The history is therefore more complex than a one-way transformation from one wild bird into every named breed. Different domestic populations can carry mosaics of ancestry. Genomic comparisons identify relationships, while archaeological evidence is needed to investigate where and when people maintained chickens. Genetic divergence from a wild population is not automatically the date of domestication. A modern breed’s identity depends on its later breeding history and standards, which occupy a different timescale from the origin of domestic chickens as a whole.