Over a third of the global population depends on rice as their staple food, and around the world we cultivate more than 140,000 varieties of the grain, according to the United Nations Food and Agriculture Organization. It's hard to overstate the crop's importance to us all, but for all that we rely on rice, we're a little lacking on the details of its origins. For the first time ever, a group of scientists were able to extract DNA from 2,800-year-old grains of rice to compare it to 200-plus modern varieties of rice from around the world, as reported in a recent article on Phys.org. Among the findings: rice may not have told the truth about where it came from.
Despite those 140,000 rice varieties, 90% of the planet’s harvest comes from merely two domesticated kinds: japonica and indica. Before this study, researchers believed that japonica rice—the short grain variety used in sushi—had been exclusively produced in the northern part of China, Japan, and Korea, and indica—made of longer grains that fluff up for pilaf and biryani—had come from tropical parts of the Asian continent. But after scientists extracted DNA from those ancient grains of rice uncovered in seven archaeological sites in Korea and Japan, they found indica’s sticky DNA.
“The research team has now found, for the first time, the presence of both japonica- and indica-type varieties in the Yayoi period and the middle ages of Japan and the middle part of Korean Peninsula 2000 years ago,” the article reads. “Together with the finding of rice variety in Korean Peninsula, the indica variety also contributed to the dietary of people living in archaic East Asia of more than two thousand years ago.”
The scientists are still unsure as to whether the western part of the Korean peninsula was cultivating indica rice more than 2,000 years ago, or if China brought the rice over during the Han Empire. What they do know now, though, is that ancient East Asians weren’t just eating japonica rice. They likely lived on a wide variety of rice cultivars, including longer-grain indica, which eventually fell victim to the homogenizing forces of domestication. Had those varieties lived on, it’s possible, given their different culinary specialties, that they would have impacted those regions’ cuisines in some surprising ways.
And if you need a reminder that knowledge is power: all of this information literally comes from a single grain of rice.