DNA from ancient skeletons confirms that migrating farmers introduced rice to Southeast Asia, including Vietnam.
Nguyen Huy Kham/REUTERS
Rice farming spread far and wide in ancient Southeast Asia, but how it got there has been a mystery. Now, a study of 4000-year-old DNA—a rare find in this region—suggests it came with farmers migrating from China, where rice farming originated. That means the hunter-gatherers already living there didn’t learn farming themselves, or from their immediate neighbors, but rather from distant people moving into their territory—a pattern that may have played out throughout this part of the globe.
The study sheds light on “a pivotal period in social and ecological history,” says Hsiao-chun Hung, an archaeologist at Australian National University in Canberra who researches the spread of farming in Southeast Asia and wasn’t involved in the new work.
Scientists have struggled to peer into the prehistory of Southeast Asia because the region’s hot, humid climate tends to degrade DNA. But David Reich, a population geneticist at Harvard University, and Ron Pinhasi, a physical anthropologist at University of Vienna, gave it a go anyway.
Pinhasi worked with archaeologists who had excavated 146 skeletons from ancient people who lived in Southeast Asia. The team then used state-of-the-art genetic sampling and sequencing techniques to recover DNA from these remains. Only 18 individuals gave up their genetic story, but that was enough to open a new window onto the past. They lived in Vietnam, Myanmar, Thailand, and Cambodia between 4100 and 1700 years ago, a period ranging from the beginning of agriculture in Southeast Asia all the way through the region’s Iron Age.
The oldest skeletons come from the site of Man Bac in northern Vietnam, where archaeologists have unearthed artifacts including decorated pottery and intricate jade ornaments that are very similar to those found at earlier rice farming sites in China. Archaeologists have long believed that indigenous hunter-gatherers and newly arrived rice and millet farmers lived together at Man Bac. And indeed, the genomes of the site’s residents confirmed that idea. They showed a mixture of two ancestries: one indigenous to the region and the other more related to people from southern China. That confirms that farmers had moved to Man Bac, spread their technology and culture, and mixed with the local population of hunter-gatherers, the team reports today in Science.