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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."

CHIAYI, Feb. 26 (Xinhua) -- Chen Yunlin, the Chinese mainland chief negotiator with Taiwan, discussed cooperation prospects on Friday with fishermen and farmers in Chiayi in southern Taiwan.Chen, president of the mainland's Association for Relations Across the Taiwan Straits (ARATS), led a 50-member delegation and spoke at a seminar attended by more than 70 business people from both the mainland and Taiwan.He said small and medium-sized enterprises on both sides "played an important role in cross-Strait economic development, employment and in maintaining social stability.""Small- and medium-sized businesses are an important part of cross-Strait economic exchanges," he said, adding that among the more than 80,000 Taiwanese enterprises investing on the mainland, over 50 percent are small and medium-sized companies.Chen said that efforts should be made to enhance cooperation between small and medium-sized enterprises on the mainland and those in central and southern Taiwan.The mainland delegation arrived in Chiayi from Kaohsiung after investigating the investment environment with local business leaders. They arrived in Taipei on Wednesday at the invitation of Chiang Pin-kung, chairman of Taiwan's Straits Exchange Foundation (SEF). Both the SEF and the ARATS are authorized by the two sides to handle cross-Strait affairs.Chen said that since 2005, the mainland bought a large amount of farm and fishing products from Taiwan, which greatly boosted sales of Taiwanese products."Many renowned mainland distribution firms are present here at the seminar to seek cooperation opportunities with Taiwan's farmers and fishermen so that the sale of Taiwanese products on the mainland could increase steadily," he said.Chiang said the farming and fishing industries were the most important sectors in southern Taiwan.He added that the tax-reduction plan of the cross-Strait Economic Cooperation Framework Agreement's (ECFA) "early harvest" program, which took effect on January 1, covered 13 categories for farming products and five categories for fishing goods. Chiang said the plan was an opportunity for the industry to expand its exports to the mainland.He noted that the "early harvest" program's duty exemption also covered sectors like textiles, machinery components, and "all related to small- and medium-sized enterprises."Chiang said Friday's seminar was meant to promote cooperation between smaller businesses across the Strait, to deepen the effect of the ECFA to benefit both sides.The mainland delegation will continue its trip in southern Taiwan and return to Taipei late Saturday. They will visit Taipei's Neihu Industrial Park on Sunday before leaving the island on Monday.

WASHINGTON, March 9 (Xinhua) -- U.S. space shuttle Discovery landed safely at the Kennedy Space Center in Florida on Wednesday, ending its nearly 27-year flying career as the world's most- traveled spaceship.According to NASA, Discovery touched down at 11:57 a.m. EST ( 1657 GMT) after a 13-day resupply mission to the International Space Station (ISS)."For the final time: wheels stop," Discovery's commander Steven Lindsey called out as the shuttle rolled to a full stop.Discovery lifted off on Feb. 24 from the Kennedy Center and arrived at the space station on Feb. 26.During the mission, the astronauts installed a spare closet module on the space station, completed some important repairs and delivered the first humanoid robot, though it will need more time to be assembled and made operational.The 330-pound R2 consists of a head and a torso with two arms and two hands. Once it is unpacked -- likely several months after its arrival at the station -- it will initially be operated inside the Destiny laboratory for operational testing, but over time both its territory and its applications could expand.Aboard the station, its primary job for now is teaching engineers how dexterous robots behave in space. However, the hope is that through upgrades and advancements, it could one day venture outside the station to help spacewalkers make repairs or additions to the station or perform scientific work.

UNITED NATIONS, Jan. 26 (Xinhua) -- China on Wednesday welcomed the smooth development of the south Sudan referendum, voicing its hope that the parties in south and north Sudan could reach a consensus at an early date on the outstanding issues through dialogue and consultations.Li Baodong, the Chinese permanent representative to the United Nations, made the statement in an interview with Xinhua after he spoke at the UN Security Council about the Chinese stance on the situation of Sudan.Earlier on Wednesday, the Security Council met to hear briefings from Atul Khare, UN assistant secretary-general for peacekeeping operations, and Ibrahim Gambari, the joint special representative of the African Union-United Nations Mission in Darfur (UNAMID), on the current situation in Sudan."China welcomes the smooth development of the south Sudan referendum, this is the result of the joint efforts of north and south Sudan and the international community," Li said."At present, priority should be given to the following work: First, continuous efforts should be made to fully maintain peace and stability in Sudan to enable the country to realize its long- term peace, stability and development," he said. "Second, efforts should be made to encourage the parties in south and north Sudan to continue their efforts for the full implementation of the Comprehensive Peace Agreement (CPA), particularly for a consensus at an early date on the outstanding issues."The referendum, with its week-long polling period ending on Jan. 15, will determine whether south Sudan remains a part of Sudan or becomes independent, in accordance with the 2005 CPA that ended a long-running north-south civil war.The referendum's preliminary results are expected to be announced by Feb. 2, and depending on whether appeals are launched in the courts, the final result will be declared on Feb. 7 or 14.

ABUJA, Jan. 28 (Xinhua) -- China and Nigeria celebrated the 40th anniversary of the establishment of diplomatic relations on Thursday evening in Nigeria's capital city Abuja.More than 600 Chinese and Nigerian guests, including Nigeria's former Head of State Yakubu Gowon, attended the gala event.On Feb. 10, 1971, the two most populous developing countries in Asia and Africa set up their diplomatic relations, said Deng Boqing, the Chinese ambassador to Nigeria.The frequent high level visits from both sides built up the mutual trust, the exchanges and cooperation in the fields of economy, culture, science, education and health, he said.The bilateral trade volume in 2010 is expected to break the record 7.5 billion U.S. dollars in 2008. The total Chinese investment in Nigeria has been nearly 8 billion dollars by the end of 2010, he said.Deng also gave tribute to the indispensable efforts made by the overseas Chinese and Chinese companies in Nigeria.Yakubu Gowon, former head of state in the 1970s, told Xinhua that he was delighted to witness the establishment of diplomatic ties between China and Nigeria in 1971 during his term. He visited China and met the late Chinese leader Mao Zedong in 1974.Nigeria's President Goodluck Jonathan sent his representative to the celebration of the 40th anniversary of bilateral ties, pledging the two countries would work closely in the future.