Sorry, turkey—around the world, more people than ever before are feasting on chicken. Despite our adoration for the humble bird, we haven’t been able to figure out which ancient society gets credit for putting it on our plates. Some scientists—including Charles Darwin—have argued that chicken domestication traces back to the Indus Valley, in what is now Pakistan and western India. Others insist that early cultures in northern China, southwest China or Southeast Asia were the original chicken whisperers.
Now scientists from China, Germany and the United Kingdom say that northern China is home the world’s earliest known chicken domestication site, based on their work sequencing genes from the oldest available chicken bones. Today northern China is a fairly dry place that plummets into Siberian temperatures in the winter. Thousands of years ago, however, it was balmy enough to host the jungle fowl that scientists think gave rise to domesticated chickens.
The researchers examined 39 bird bones recovered from three archaeological sites along the Yellow River in northern China and one site in eastern China. The remains were found alongside charcoal and bones from other animals, including pigs, dogs and—in one case—tigers and Chinese alligators. The bones range in age from 2,300 to 10,500 years old, which the scientists determined using radiocarbon dating. Prior to this study, the oldest chicken sequences came from birds that lived around 4,000 years ago.
Next, the team used recently developed methods to sequence mitochondrial DNA extracted from the bones and compared those sequences with others taken from 1,000-year-old bones found in Spain, Hawaii, Easter Island and Chile. They compared all of those ancient birds’ genetics with those of modern day chickens and chicken relatives, including pheasants and partridges.
According to the analysis, published today in the Proceedings of the National Academy of Sciences, all of the chicken bones from China belong to the genus Gallus, the same as modern day jungle fowl and domesticated chickens. The bones were recovered from ancient agricultural sites over thousands of years, hinting that the birds might have been living there alongside humans and their crops. They also date to around the same time as early pig domestication in the same part of China. Additionally, the ancient chickens share one of the most common haplotypes—clusters of closely linked genes—with modern chickens, suggesting that the Chinese chickens were at least one of the original varieties that eventually spread across the world.
The chicken domestication riddle, however, is not definitively solved. It’s impossible to tell from those sequences alone whether the chickens in question were truly domestic or wild. And the authors suspect that other societies in South Asia, Southeast Asia and South America were busy domesticating their own chickens around the same time as the northern Chinese. It could be that chickens were domesticated in many places and have acquired a patchwork genome as they spread and interbred that reflects their varied origins. Testing that hypothesis, however, will have to wait until researchers manage to uncover yet more picked-over remains of similarly ancient chicken dinners.