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WASHINGTON, May 2 (Xinhua) -- Rice originated in China, a team of U.S. genome researchers has concluded in a study tracing back thousands of years of evolutionary history through large-scale gene re-sequencing.Their findings, which appear Monday in the latest issue of the Proceedings of the National Academy of Sciences (PNAS), indicate that domesticated rice may have first appeared as far back as approximately 9,000 years ago in the Yangtze Valley of China. Previous research suggested domesticated rice may have two points of origin -- India as well as China.Asian rice, Oryza sativa, is one of world's oldest crop species. It is also a very diverse crop, with tens of thousands of varieties known throughout the world. Two major subspecies of rice -- japonica and indica -- represent most of the world's varieties. Sushi rice, for example, is a type of japonica, while most of the long-grain rice in risottos are indica.Because rice is so diverse, its origins have been the subject of scientific debate. One theory -- a single-origin model -- suggests that indica and japonica were domesticated once from the wild rice O. rufipogon.Another -- a multiple-origin model -- proposes that these two major rice types were domesticated separately and in different parts of Asia. The multiple-origin model has gained currency in recent years as biologists have observed significant genetic differences between indica and japonica, and several studies examining the evolutionary relationships among rice varieties supported more than domestication in both India and China.In the PNAS study, the researchers re-assessed the evolutionary history, or phylogeny, of domesticated rice using previously published datasets, some of which have been used to argue that indica and japonica rice have separate origins. Using more modern computer algorithms, however, the researchers concluded these two species have the same origin because they have a closer genetic relationship to each other than to any wild rice species found in either India or China.In addition, the study's authors 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. Using new modeling techniques, which had previously been used to look at genomic data in human evolution, their results showed that the gene sequence data was more consistent with a single origin of rice.In the study, the investigators also used a "molecular clock" of rice genes to see when rice evolved. Depending on how the researchers calibrated their clock, they pinpointed the origin of rice at possibly 8,200 years ago, while japonica and indica split apart from each other about 3,900 years ago. The study's authors pointed out that these molecular dates were consistent with archaeological studies.Archaeologists have uncovered evidence in the last decade for rice domestication in the Yangtze Valley beginning approximately 8, 000 to 9,000 years ago while 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," explained New York University biologist Michael Purugganan, one of the study's co-authors. "So domesticated rice that we may have once thought originated in India actually has its beginnings in China."

BEIJING, Feb. 26 (Xinhua) -- Zhu Guangya, who contributed to the development of China's first atom and hydrogen bombs, died Saturday at age 87.Zhu was a senior academician at the Chinese Academy of Sciences and the Chinese Academy of Engineering. He served as vice chairman of the National Committee of the Chinese People's Political Consultative Conference, China's top political advisory body, between 1994 and 2003.Born in central China's Yichang city, Zhu obtained a PhD in nuclear physics from the University of Michigan in 1950. That year he returned to China. He joined the Communist Party of China in 1956.

CHICAGO, Jan. 21 (Xinhua) -- Chinese President Hu Jintao left Chicago for China on Friday after concluding a state visit to the United States, during which he and his U.S. counterpart Barack Obama agreed to build a China-U.S. cooperative partnership based on mutual respect and mutual benefit.Hu, who began his four-day visit Tuesday, had extensive and in-depth discussions with Obama at the White House on Wednesday on major bilateral, regional and world issues.Chinese President Hu Jintao shakes hands with U.S. President Barack Obama during a bilateral meeting at the White House in Washington, the United States, Jan. 19, 2011.The two sides reached "important agreement on China-U.S. relations and major international and regional issues of shared interests," the Chinese president said when he and Obama met the press following their discussions."We both agree to further push forward the positive, cooperative and comprehensive China-U.S. relationship," Hu said, adding that both sides also pledged to forge "a China-U.S. cooperative partnership based on mutual respect and mutual benefit" for the benefit of the two countries and beyond.

LONDON, March 15 (Xinhua) -- The moon would be in a "super position" on Saturday, which makes it a "supermoon" and the web is awash with myths about its implications such as connection to recent earthquakes, but that's not the case according to British experts.Technically the so-called "supermoon" means that the moon would be in its perigee, the closest point to earth in its orbit on March 19, and on top of that, it would also be a full moon at the same time.The massive earthquake in Japan just fueled the speculation that the gravitational pull of the "supermoon" will bring chaos to the Earth, such as earthquakes and volcanic activities.But "there is little that is special about perigee on March 19," said Dr. Robert Massey, deputy executive secretary of the Royal Astronomical Society. He said the moon will be around 360,000 km from the earth on that day, but this has happened at least 15 times during the last 400 years."There is no reason whatsoever to believe that there is a connection between the so-called 'supermoon' and the recent earthquake," Massey told Xinhua. "There are also no other 'abnormal' phenomena connected with a 'supermoon' other than the high tides that we experience twice every month."Massey was echoed by Dr. Bruce Malamud, a geophysicist in the Department of Geography at King's College London, who that: "A supermoon will not be able to actually influence at all the internal workings of our Planet Earth, as there is so much momentum and mass already stored up, that the actual effect is negligible.""The earthquake took place a full 8 days before the 'supermoon' meaning that the tidal forces exerted by the moon and sun together were near their minimum rather than maximum level, directly contradicting the fearmongers," said Massey.Calling the "supermoon" claims "bogus science," he questioned the motives of those who made such claims on the day that thousands of people died in a severe earthquake and the ensuing tsunami.

BEIJING, Jan. 25 (Xinhua) -- A senior Chinese official has encouraged the country's young jurists to more actively participate in the country's legislative process and better serve the practice of law enforcement.Zhou Yongkang, a member of the Standing Committee of the Political Bureau of the Communist Party of China (CPC) Central Committee, made the remarks in meeting with outstanding youth law science experts on Tuesday in Beijing.Zhou said young experts on law science should pay more attention to practical problems in China's legal construction and propose more insights, advice and suggestions.Young experts should study more problems encountered by common people and better serve the people with their knowledge, Zhou said.Ten experts on law science from the Renmin University of China, China University of Political Science and Law and other universities and Chinese Academy of Social Sciences were awarded the honor of national outstanding young jurists by the China Law Society.

来源：资阳报