Y chromosome diversity, human expansion, drift, and cultural evolution
Y chromosome diversity, human expansion, drift, and cultural evolution
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DOI：
10.1073/pnas.0910803106
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发表时间：
2009-12-01
影响因子：
11.1
通讯作者：
Cavalli-Sforza, Luca L.
中科院分区：
文献类型：
--
作者：
Chiaroni, Jacques;Underhill, Peter A.;Cavalli-Sforza, Luca L.
适应和机会在决定遗传多样性和进化方面的相对重要性在过去 50 年里受到了人们的关注，但我们的理解仍然不完整。所有关于进化因素（尤其是漂移）相对影响的陈述都需要通过强有力的人口统计观察来证实，其中一些在像我们这样的物种中更容易获得。早期对各种数据的定量研究表明，现存人类群体中遗传分化的程度表明，正向（或定向）选择的作用是有限的。我们观察到一些 Y 染色体突变体的地理特征，很可能是由于一种称为冲浪效应的与漂移相关的现象。我们还将 Y 染色体 DNA 数据中的整体遗传多样性与其他染色体的遗传多样性及其在漂移和自然选择下的预期进行比较，以及在现代人类最近“走出非洲”向全世界扩张期间被称为系列创始人效应的种群内多样性下降的速度。如果不承认漂移在人类扩张过程中的主要相对作用，所有这些观察结果都很难解释。人类创造力的日益增强和发明的快速传播似乎有利于解决扩张中遇到的许多问题的文化解决方案。我们认为，文化进化已经取代了生物进化，提供了自然选择优势并减少了我们对基因突变的依赖，特别是在从食物采集到食物生产的最后阶段。
The relative importance of the roles of adaptation and chance in determining genetic diversity and evolution has received attention in the last 50 years, but our understanding is still incomplete. All statements about the relative effects of evolutionary factors, especially drift, need confirmation by strong demographic observations, some of which are easier to obtain in a species like ours. Earlier quantitative studies on a variety of data have shown that the amount of genetic differentiation in living human populations indicates that the role of positive (or directional) selection is modest. We observe geographic peculiarities with some Y chromosome mutants, most probably due to a drift-related phenomenon called the surfing effect. We also compare the overall genetic diversity in Y chromosome DNA data with that of other chromosomes and their expectations under drift and natural selection, as well as the rate of fall of diversity within populations known as the serial founder effect during the recent "Out of Africa" expansion of modern humans to the whole world. All these observations are difficult to explain without accepting a major relative role for drift in the course of human expansions. The increasing role of human creativity and the fast diffusion of inventions seem to have favored cultural solutions for many of the problems encountered in the expansion. We suggest that cultural evolution has been subrogating biologic evolution in providing natural selection advantages and reducing our dependence on genetic mutations, especially in the last phase of transition from food collection to food production.