Based on an analysis of select genetic regions, a study in PNAS last month concluded that the two main subspecies of rice, indica and japonica, both originated in China's Yangtze Valley. But as The New York Times reports, another study in PLoS Genetics found the origins of rice aren't that simple. The Beijing Institute of Genomics' Chung-I Wu and his colleagues sequenced both subspecies of rice to compare their full genomes. "While indica and japonica genomes generally appear to be of independent origin, many overlapping LDRs [low diversity regions] may have originated only once, as a result of selection and subsequent introgression," the authors write in PLoS Genetics.
"Somebody might have given a neighboring village the rice, and then it went to the next village," Wu tells the Times. "Over 100 years, traits may have traveled 1,000 or 2,000 kilometers."