Chikhi L, Destro-Bisol G, Bertorelle G, Pascali V, Barbujani G
Dipartimento di Biologia, Università di Ferrara, via Borsari 46, 44100 Ferrara, Italy.
Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):9053-8. doi: 10.1073/pnas.95.15.9053.
Comparisons between archaeological findings and allele frequencies at protein loci suggest that most genes of current Europeans descend from populations that have been expanding in Europe in the last 10, 000 years, in the Neolithic period. Recent mitochondrial data have been interpreted as indicating a much older, Paleolithic ancestry. In a spatial autocorrelation study at seven hypervariable loci in Europe (four microsatellites, two larger, tandem-repeat loci, and a sequence polymorphism) broad clinal patterns of DNA variation were recognized. The observed clines closely match those described at the protein level, in agreement with a possible Near Eastern origin for the ancestral population. Separation times between populations were estimated on the basis of a stepwise mutation model. Even assuming low mutation rates and long generation times, we found no evidence for population splits older than 10,000 years, with the predictable exception of Saami (Lapps). The simplest interpretation of these results is that the current nuclear gene pool largely reflects the westward and northward expansion of a Neolithic group. This conclusion is now supported by purely genetic evidence on the levels and patterns of microsatellite diversity, rather than by correlations of biological and nonbiological data. We argue that many mitochondrial lineages whose origin has been traced back to the Paleolithic period probably reached Europe at a later time.
考古发现与蛋白质位点等位基因频率之间的比较表明,现代欧洲人的大多数基因源自新石器时代(即过去一万年里)在欧洲不断扩张的人群。最近的线粒体数据被解读为表明有着更为古老的旧石器时代祖先。在一项针对欧洲七个高变位点(四个微卫星、两个较大的串联重复位点以及一个序列多态性位点)的空间自相关研究中,识别出了广泛的DNA变异渐变模式。观察到的渐变与蛋白质水平上所描述的渐变紧密匹配,这与祖先群体可能起源于近东地区的观点一致。基于逐步突变模型估计了群体之间的分离时间。即使假设突变率低且世代时间长,除了萨米人(拉普人)这一可预见的例外情况,我们没有发现超过一万年的群体分裂证据。对这些结果最简单的解释是,当前的核基因库在很大程度上反映了一个新石器时代群体的向西和向北扩张。这一结论现在得到了关于微卫星多样性水平和模式的纯遗传学证据的支持,而非生物数据与非生物数据的相关性支持。我们认为,许多起源可追溯到旧石器时代的线粒体谱系可能是在更晚的时候到达欧洲的。