But, don't worry: it's perfectly safe. Yes, according to a team of researchers at Cornell University, close to 97.9% of all white rice is derived from a mutation in a gene originating in the Japonica subspecies which occurred about 10,000 years ago. The mutation produces a shortened version of a protein normally responsible for activating the molecular pathway leading to color in rice grains. They believe it was allowed to spread around the world by early farmers who favored the white rice over other grain varieties.
Not only did the white rice varieties cook faster, the researchers also theorize that their hulls were much easier to remove compared to red rice and that disease and insects were more visible amid the grains. The women who shucked the rice thousands of years ago may have picked out specific panicles — grain clusters on the stems — for planting and breeding purposes.Researchers first identified the gene responsible for rendering the rice seed's pericarp, or bran layer, white last year — which gave them the genetic marker necessary to develop new breeds that were hardier and had improved yields. In doing so, they typically select against the gene for pericarp — which is link to such unfavorable "weedy" related traits as seed dormancy and shattering (when seeds fall easily from the stalk). This knowledge may lead to the breeding of several new domestic rice varieties in the coming years.
"Breeders can now begin to screen for the red pericarp gene while selecting against closely linked traits like shattering and dormancy," said Susan McCouch, a professor of plant breeding and genetics at Cornell and the study's lead scientist. Who knows what mutated variety of rice our descendants will be eating 10,000 years from now?