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Tuesday, May 3, 2011

Rice originated 9,000 years ago in China, say genome researchers

In a study tracing back thousands of years of evolutionary history through large-scale gene re-sequencing, a team of genome researchers has concluded that rice originated in China.
Their findings indicated that domesticated rice might have first appeared as far back as approximately 9,000 years ago in the Yangtze Valley of China.
Researchers from New York University's Center for Genomics and Systems Biology and its Department of Biology, Washington University in St. Louis' Department of Biology, Stanford University's Department of Genetics, and Purdue University's Department of Agronomy were behind the study.
Previous research suggested domesticated rice may have two points of origin-India as well as China.
The researchers examined the phylogeny of domesticated rice by re-sequencing 630 gene fragments on selected chromosomes from a diverse set of wild and domesticated rice varieties.
Their results showed that the gene sequence data was more consistent with a single origin of rice.
They also used a "molecular clock" of rice genes to see when rice evolved and pinpointed the origin of rice at possibly 8,200 years ago.
The study's authors pointed out that these molecular dates were consistent with archaeological evidence uncovered in the last decade for rice domestication in the Yangtze Valley beginning approximately 8,000 to 9,000 years ago.
And domestication of rice in the India's Ganges region was around about 4,000 years ago.
"As rice was brought in from China to India by traders and migrant farmers, it likely hybridized extensively with local wild rice. So domesticated rice that we may have once thought originated in India actually has its beginnings in China," said NYU biologist Michael Purugganan, one of the study's co-authors.
The findings appeared in the latest issue of the Proceedings of the National Academy of Sciences (PNAS). (ANI)