最新一期美國《公共科學(xué)圖書館—綜合》(PLoS one)刊發(fā)了復(fù)旦大學(xué)現(xiàn)代人類學(xué)教育部重點(diǎn)實(shí)驗(yàn)室的一項(xiàng)成果,，其中提出了農(nóng)業(yè)產(chǎn)生的新假說，即東亞人群的擴(kuò)張?jiān)斐傻氖澄镄枨罂赡苁寝r(nóng)業(yè)產(chǎn)生的主要動因,，而農(nóng)業(yè)的產(chǎn)生和發(fā)展進(jìn)一步推動了人群的繼續(xù)擴(kuò)張,。
項(xiàng)目負(fù)責(zé)人之一、復(fù)旦大學(xué)教授金力10月8日介紹,，農(nóng)業(yè)起源時間大約在距今6000年到8000年間,，不過早期的農(nóng)作物是屬于補(bǔ)充性食物，并非食物的主要來源,，形成真正的農(nóng)業(yè)大約是4000年到6000年之間,。此前科學(xué)家們大多認(rèn)為，有了農(nóng)業(yè)文明才有了人群增長,。
此次研究團(tuán)隊(duì)對一個隨機(jī)采取的樣本,、共367個個體的線粒體全基因組進(jìn)行了分析，其中包括249個中國人和118個日本人,。結(jié)果發(fā)現(xiàn),，除了兩個日本特有的支系外，所有的東亞人群中的主要支系均在13000年前發(fā)生了擴(kuò)張,，這個時間明顯早于一般認(rèn)為的農(nóng)業(yè)起源時間,。東亞地區(qū)人群的擴(kuò)張,，顯然早于農(nóng)業(yè)文明。
金力介紹,，大約在距今15000年前,，東亞地區(qū)重要的氣候改變期——末次盛冰期結(jié)束了。冰川開始消退,，氣候變暖,；植被開始茂盛，動物數(shù)量也隨之增加,。研究團(tuán)隊(duì)因此推論,，隨著當(dāng)時食物的豐富人群開始擴(kuò)張，隨著人口數(shù)量增加食物需求也增加了,，因而農(nóng)業(yè)也進(jìn)一步發(fā)達(dá)起來,。而農(nóng)業(yè)的產(chǎn)生和發(fā)展又進(jìn)一步推動了人群的繼續(xù)擴(kuò)張。
《公共科學(xué)圖書館》是一家由眾多諾貝爾獎得主和慈善機(jī)構(gòu)支持的非贏利性學(xué)術(shù)組織,，旨在推廣世界各地的科學(xué)和醫(yī)學(xué)領(lǐng)域的最新研究成果,。該期刊被認(rèn)為探索性較強(qiáng)。（生物谷 Bioon.com)
doi:10.1371/journal.pone.0025835
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Major Population Expansion of East Asians Began before Neolithic Time: Evidence of mtDNA Genomes
Hong-Xiang Zheng, Shi Yan, Zhen-Dong Qin, Yi Wang, Jing-Ze Tan, Hui Li, Li Jin
It is a major question in archaeology and anthropology whether human populations started to grow primarily after the advent of agriculture, i.e., the Neolithic time, especially in East Asia, which was one of the centers of ancient agricultural civilization. To answer this question requires an accurate estimation of the time of lineage expansion as well as that of population expansion in a population sample without ascertainment bias. In this study, we analyzed all available mtDNA genomes of East Asians ascertained by random sampling, a total of 367 complete mtDNA sequences generated by the 1000 Genome Project, including 249 Chinese (CHB, CHD, and CHS) and 118 Japanese (JPT). We found that major mtDNA lineages underwent expansions, all of which, except for two JPT-specific lineages, including D4, D4b2b, D4a, D4j, D5a2a, A, N9a, F1a1'4, F2, B4, B4a, G2a1 and M7b1'2'4, occurred before 10 kya, i.e., before the Neolithic time (symbolized by Dadiwan Culture at 7.9 kya) in East Asia. Consistent to this observation, the further analysis showed that the population expansion in East Asia started at 13 kya and lasted until 4 kya. The results suggest that the population growth in East Asia constituted a need for the introduction of agriculture and might be one of the driving forces that led to the further development of agriculture.
