Mellars Paul
Department of Archaeology, Cambridge University, Downing Street, Cambridge CB2 3DZ, England.
Proc Natl Acad Sci U S A. 2006 Jun 20;103(25):9381-6. doi: 10.1073/pnas.0510792103. Epub 2006 Jun 13.
Recent research has provided increasing support for the origins of anatomically and genetically "modern" human populations in Africa between 150,000 and 200,000 years ago, followed by a major dispersal of these populations to both Asia and Europe sometime after ca. 65,000 before present (B.P.). However, the central question of why it took these populations approximately 100,000 years to disperse from Africa to other regions of the world has never been clearly resolved. It is suggested here that the answer may lie partly in the results of recent DNA studies of present-day African populations, combined with a spate of new archaeological discoveries in Africa. Studies of both the mitochondrial DNA (mtDNA) mismatch patterns in modern African populations and related mtDNA lineage-analysis patterns point to a major demographic expansion centered broadly within the time range from 80,000 to 60,000 B.P., probably deriving from a small geographical region of Africa. Recent archaeological discoveries in southern and eastern Africa suggest that, at approximately the same time, there was a major increase in the complexity of the technological, economic, social, and cognitive behavior of certain African groups, which could have led to a major demographic expansion of these groups in competition with other, adjacent groups. It is suggested that this complex of behavioral changes (possibly triggered by the rapid environmental changes around the transition from oxygen isotope stage 5 to stage 4) could have led not only to the expansion of the L2 and L3 mitochondrial lineages over the whole of Africa but also to the ensuing dispersal of these modern populations over most regions of Asia, Australasia, and Europe, and their replacement (with or without interbreeding) of the preceding "archaic" populations in these regions.
最近的研究越来越支持解剖学和遗传学上“现代”人类种群于15万至20万年前起源于非洲，随后在距今约6.5万年前的某个时候，这些种群大规模扩散至亚洲和欧洲。然而，这些种群为何花了大约10万年才从非洲扩散到世界其他地区这一核心问题从未得到明确解决。本文认为，答案可能部分在于对当今非洲人群的最新DNA研究结果，以及非洲一系列新的考古发现。对现代非洲人群线粒体DNA（mtDNA）错配模式和相关mtDNA谱系分析模式的研究表明，在距今8万至6万年前的时间范围内，可能源自非洲一个小地理区域，出现了一次以广泛区域为中心的主要人口扩张。非洲南部和东部最近的考古发现表明，大约在同一时间，某些非洲群体的技术、经济、社会和认知行为复杂性大幅增加，这可能导致这些群体在与其他相邻群体的竞争中出现主要人口扩张。有人认为，这种行为变化的复合体（可能由从氧同位素阶段5到阶段4过渡期间的快速环境变化引发）不仅可能导致L2和L3线粒体谱系在整个非洲的扩张，还可能导致这些现代人群随后扩散到亚洲、澳大拉西亚和欧洲的大部分地区，并在这些地区取代（有或没有杂交）先前的“古代”人群。
