Jin L, Underhill P A, Doctor V, Davis R W, Shen P, Cavalli-Sforza L L, Oefner P J
Department of Genetics, Stanford University, Stanford, CA 94305, USA.
Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3796-800. doi: 10.1073/pnas.96.7.3796.
Despite mounting genetic evidence implicating a recent origin of modern humans, the elucidation of early migratory gene-flow episodes remains incomplete. Geographic distribution of haplotypes may show traces of ancestral migrations. However, such evolutionary signatures can be erased easily by recombination and mutational perturbations. A 565-bp chromosome 21 region near the MX1 gene, which contains nine sites frequently polymorphic in human populations, has been found. It is unaffected by recombination and recurrent mutation and thus reflects only migratory history, genetic drift, and possibly selection. Geographic distribution of contemporary haplotypes implies distinctive prehistoric human migrations: one to Oceania, one to Asia and subsequently to America, and a third one predominantly to Europe. The findings with chromosome 21 are confirmed by independent evidence from a Y chromosome phylogeny. Loci of this type will help to decipher the evolutionary history of modern humans.
尽管越来越多的遗传学证据表明现代人类起源较近，但早期迁徙基因流事件的阐释仍不完整。单倍型的地理分布可能显示出祖先迁徙的痕迹。然而，这种进化特征很容易被重组和突变扰动抹去。在MX1基因附近发现了一个位于21号染色体上的565碱基对区域，该区域包含九个在人类群体中经常出现多态性的位点。它不受重组和反复突变的影响，因此仅反映迁徙历史、遗传漂变以及可能的选择。当代单倍型的地理分布意味着独特的史前人类迁徙：一次到大洋洲，一次到亚洲，随后到美洲，第三次主要到欧洲。来自Y染色体系统发育的独立证据证实了21号染色体的研究结果。这类基因座将有助于解读现代人类的进化历史。
