最新一期美国《公共科学图书馆—综合》(PLoS one)刊发了复旦大学现代人类学教育部重点实验室的一项成果，其中提出了农业产生的新假说，即东亚人群的扩张造成的食物需求可能是农业产生的主要动因，而农业的产生和发展进一步推动了人群的继续扩张。
项目负责人之一、复旦大学教授金力10月8日介绍，农业起源时间大约在距今6000年到8000年间，不过早期的农作物是属于补充性食物，并非食物的主要来源，形成真正的农业大约是4000年到6000年之间。此前科学家们大多认为，有了农业文明才有了人群增长。
此次研究团队对一个随机采取的样本、共367个个体的线粒体全基因组进行了分析，其中包括249个中国人和118个日本人。结果发现，除了两个日本特有的支系外，所有的东亚人群中的主要支系均在13000年前发生了扩张，这个时间明显早于一般认为的农业起源时间。东亚地区人群的扩张，显然早于农业文明。
金力介绍，大约在距今15000年前，东亚地区重要的气候改变期——末次盛冰期结束了。冰川开始消退，气候变暖；植被开始茂盛，动物数量也随之增加。研究团队因此推论，随着当时食物的丰富人群开始扩张，随着人口数量增加食物需求也增加了，因而农业也进一步发达起来。而农业的产生和发展又进一步推动了人群的继续扩张。
《公共科学图书馆》是一家由众多诺贝尔奖得主和慈善机构支持的非赢利性学术组织，旨在推广世界各地的科学和医学领域的最新研究成果。该期刊被认为探索性较强。（生物谷 Bioon.com)
doi:10.1371/journal.pone.0025835
PMC:
PMID:
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.
