Chicken is the world's most popular animal, the largest source of animal protein for mankind. The chicken population is about 24 billion, outperforming all other birds in terms of numbers. For the past two centuries, biologists have sought ways to explain the origins of today's domesticated chickens.
And now, the first in-depth study of the bird's full genome concludes that, around 7,500 BC, people in northern Southeast Asia, or southern China, domesticated a pheasant. colorful red. Migrants and merchants then took the bird across Asia and to every continent except Antarctica.
A subspecies of red jungle fowl (Gallus gallus spadiceus), found in north-east Asia, is likely to lead to the first domesticated chickens.
The team led by Dr. Ming-Shan Wang of the Kunming Zoological Institute of the Chinese Academy of Sciences published a paper published in Cell Research that the results of this study contradict the claims. previously, chickens were domesticated in northern China and the Indian River basin. They also discovered that the ancestor of modern chickens was a subspecies of the red junglefowl called Gallus gallus spadiceus .
Archaeologist Dorian Fuller, University College London, who was not involved in the study, judged it to be a landmark study. The results of the study could shed light on the emergence of early agriculture and trade networks, and what characteristics of this bird make it appealing to humans.
Scientist Charles Darwin once argued that the chicken comes from the red junglefowl. He speculated that domestication was happening in India. But there are five breeds of pheasants living in a wide arc extending from the forests of Indonesia to the foothills of Pakistan. Which breed leads to chicken, and where is not sure. Based on the hypothetical chicken bones, archaeologists once claimed that humans domesticated this bird 9,000 years ago in northern China and 4,000 years ago in Pakistan.
DNA studies promise to solve this problem. So, geneticist Jianlin Han, Laboratory of Animal Genetic Resources and Animal Feed in China, embarked on a 20-year project to sample native village chickens and wild forests in China. More than 120 villages across Asia and Africa.
The red area is thought to have domesticated wild birds into domestic chickens today.
Dr. Wang's team sequenced the full 863 bird genome and compared them. The results show that modern chickens are derived primarily from domesticated and wild breeds in what is now Myanmar, Laos, Thailand and southern China. The area is a domestication center, says Nottingham geneticist Olivier Hanotte, co-author. This result confirms a hypothesis made in 1994 by Japanese Prince Akishino, a bird researcher, based on mitochondrial DNA data.
Dr. Wang's team has found some evidence for South Asia's contribution: A forest bird native to the Indian subcontinent could have been interspersed with chickens after initial domestication in Southeast Asia.
Male pheasant Gallus gallus spadiceus in India. (Image: Wikimedia).
Fuller archaeologist suspects that the bird was completely domesticated before the arrival of rice and millet in northern Southeast Asia some 4,500 years ago. As the geneticist Hanotte admits, it is necessary to have the help of archaeologists to understand the human events that create domestication.
But Jonathan Kenoyer, an archaeologist and civilization expert at the Indian River basin at the University of Wisconsin, Madison, is still skeptical that chicken farming originated in Southeast Asia. Researchers need to take ancient DNA to match their claims, because the modern bird genome may provide limited clues to the early events in evolution. Chicken, the scientist countered.
Pheasant Gallus gallus gallad spadiceus in India. (Image: Wikimedia).
Research on DNA also does not show the first things that make humans domesticate birds. Early bird varieties produced fewer eggs than today's industrial chickens. Some researchers argue that the bird was initially appreciated because its exotic plumage may have been domesticated into fighting birds. Fighting fowl is still a lucrative business in Southeast Asia and the bird's high value may have motivated traders to take them long distances.
Meanwhile, the team of geneticist Jianlin Han is creating a giant dataset based on more than 1,500 modern chicken genomes from Asia, Europe and Africa. The researchers plan to analyze the dispersion of chickens into Europe and Africa, as well as the genetic variations behind traits such as the ability to fight off disease or produce more eggs. According to Han, the research opens up a whole new page on the chicken genome.