美國研究人員在一項(xiàng)通過大規(guī)?；蛑販y序分析稻米進(jìn)化史的研究中確認(rèn),，亞洲栽培稻起源于中國，最早可能8000多年前就出現(xiàn)在中國長江流域,。
亞洲栽培稻是世界上最古老的農(nóng)作物物種之一,。此前曾有研究認(rèn)為,，亞洲栽培稻有兩個(gè)起源地——印度和中國,。但5月2日刊登在美國《國家科學(xué)院院刊》（PNAS）一項(xiàng)新研究說：“分子學(xué)證據(jù)表明（亞洲）栽培稻只有單一起源……最早出現(xiàn)在中國長江流域。”
亞洲栽培稻具有秈稻和粳稻兩個(gè)主要亞種,，其起源相應(yīng)也出現(xiàn)兩種理論,，其中一種為單一起源理論，即秈稻和粳稻均由野生稻栽培而來,；而另一種多起源理論認(rèn)為,，秈稻和粳稻在亞洲不同地點(diǎn)分別栽培而來。近年來,，由于科學(xué)界觀測到秈稻和粳稻更多的遺傳差異性,，多起源理論稍占上風(fēng)。
美國紐約大學(xué)等機(jī)構(gòu)的研究人員利用此前已公布的數(shù)據(jù)庫以及更先進(jìn)的計(jì)算機(jī)運(yùn)算規(guī)則,，重新分析了亞洲栽培稻的進(jìn)化史,。他們的結(jié)論是，秈稻和粳稻具有同一起源,，因?yàn)槎弑M管具有諸多遺傳差異性,，但彼此間的遺傳關(guān)系仍比與印度或中國發(fā)現(xiàn)的任何野生稻種類的遺傳關(guān)系都要近。
他們還對(duì)栽培稻和野生稻染色體上630個(gè)基因片段進(jìn)行了重測序,，結(jié)果也是基因測序數(shù)據(jù)與單起源理論更一致,。
研究人員利用稻米基因的分子鐘分析了亞洲栽培稻的進(jìn)化時(shí)間。他們認(rèn)為,，亞洲栽培稻大約8200年前開始出現(xiàn),，而秈稻和粳稻在大約3900年前開始分離。
這一結(jié)論與考古學(xué)發(fā)現(xiàn)相一致,?？脊艑W(xué)家發(fā)現(xiàn)，中國長江流域8000年至9000年前出現(xiàn)了栽培稻,，而印度恒河流域大約4000年前才開始出現(xiàn)栽培稻,。
參與研究的紐約大學(xué)生物學(xué)家邁克爾·普魯加南說：“隨著栽培稻通過商人以及農(nóng)民由中國傳入印度，它很可能與當(dāng)?shù)匾吧具M(jìn)行了大范圍雜交,，這就是為什么我們?cè)J(rèn)為栽培稻可能起源于印度,，但實(shí)際上是來自于中國,。”（生物谷Bioon.com）
生物谷推薦原文出處：
Proceedings of the National Academy of Sciences DOI： 10.1073/pnas.1104686108
Molecular evidence for a single evolutionary origin of domesticated rice
Molina, Jeanmaire; Sikora, Martin; Garud, Nandita; Flowers, Jonathan M.; Rubinstein, Samara; Reynolds, Andy; Huang, Pu; Jackson, Scott; Schaal, Barbara A.; Bustamante, Carlos D.; Boyko, Adam R.; Purugganan, Michael D
Asian rice, Oryza sativa, is one of world's oldest and most important crop species. Rice is believed to have been domesticated ?9,000 y ago, althoughdebate on its origin remains contentious. A single-origin model suggests that two main subspecies of Asian rice, indica and japonica, were domesticated from the wild rice O. rufipogon. In contrast, the multiple independent domestication model proposes that these two major rice types were domesticated separatelyand in different parts of the species range of wild rice. This latter view has gained much support from the observation ofstrong genetic differentiation between indica and japonica as well as several phylogenetic studies of rice domestication. We reexamine the evolutionary history of domesticated riceby resequencing 630 gene fragments on chromosomes 8, 10, and 12 from a diverse set of wild and domesticated rice accessions.Using patterns of SNPs, we identify 20 putative selective sweeps on these chromosomes in cultivated rice. Demographic modelingbased on these SNP data and a diffusion-based approach provide the strongest support for a single domestication origin ofrice. Bayesian phylogenetic analyses implementing the multispecies coalescent and using previously published phylogeneticsequence datasets also point to a single origin of Asian domesticated rice. Finally, we date the origin of domestication at?8,200–13,500 y ago, depending on the molecular clock estimate that is used, which is consistent with known archaeologicaldata that suggests rice was first cultivated at around this time in the Yangtze Valley of China.
