Durham University researchers have used ancient DNA to study how a jungle bird transformed into the domestic chicken. According to the researchers, chickens that lived 2000 to 3000 years ago looked quite different from today’s barnyard chickens. The study shows that chickens have accumulated certain traits recently. A common trait, such as the yellow skin color, for example, evolved just 500 years ago.
More than 10,000 years ago, our ancestors began to expand their organization of food production—purposefully promoting certain plants and animals they found tasty or useful. Over time, they domesticated those species, inserting human preferences into the process of natural selection. We know today that agriculture and domesticated species arose separately in different regions around the world. Grains, beans, and livestock appear to be some of the earliest species domesticated in Southwest Asia, for example. But many questions remain about why humans shifted from hunting and gathering to agriculture and how the process of domesticating species unfolded—a process that, in cases like wheat and rice, appears to have taken more than a thousand years.