Marroig Gabriel, Cheverud James M
Departamento de Biologia, Instituto de Biociências, Universidade de Sao Pãulo, Brazil.
Am Nat. 2004 Mar;163(3):417-28. doi: 10.1086/381693. Epub 2004 Jan 14.
A central controversy among biologists is the relative importance of natural selection and genetic drift as creative forces shaping biological diversification (Fisher 1930; Wright 1931). Historically, this controversy has been an effective engine powering several evolutionary research programs during the last century (Provine 1989). While all biologists agree that both processes operate in nature to produce evolutionary change, there is a diversity of opinion about which process dominates at any particular organizational level (from DNA and proteins to complex morphologies). To address this last level, we did a broadscale analysis of cranial diversification among all living New World monkeys. Quantitative genetic models yield specific predictions about the relationship between variation patterns within and between populations that may be used to test the hypothesis that genetic drift is a sufficient explanation for morphological diversification. Diversity at several levels in a hierarchy of taxonomic/phylogenetics relationship was examined from species within genera to families within superfamilies. The major conclusion is that genetic drift can be ruled out as the primary source of evolutionary diversification in cranial morphology among taxa at the level of the genus and above as well as for diversification of most genera. However, drift may account for diversification among species within some Neotropical primate genera, implying that morphological diversification associated with speciation need not be adaptive in some radiations.
生物学家之间的一个核心争议是自然选择和遗传漂变作为塑造生物多样性的创造性力量的相对重要性（费舍尔，1930年；赖特，1931年）。从历史上看，这场争议一直是推动上世纪几个进化研究项目的有效动力（普罗文，1989年）。虽然所有生物学家都同意这两个过程在自然界中都会起作用以产生进化变化，但对于在任何特定组织层次（从DNA和蛋白质到复杂形态）上哪个过程占主导地位，存在多种观点。为了解决最后这个层次的问题，我们对所有现存新大陆猴的颅骨多样性进行了大规模分析。数量遗传模型对种群内部和种群之间的变异模式之间的关系产生了具体预测，这些预测可用于检验遗传漂变是形态多样性的充分解释这一假设。从属内的物种到超科内的科，我们研究了分类学/系统发育关系层次结构中几个层次的多样性。主要结论是，在属及以上分类单元的颅骨形态进化多样性以及大多数属的多样性方面，遗传漂变可以被排除为主要来源。然而，漂变可能解释了一些新热带灵长类属内物种之间的多样性，这意味着与物种形成相关的形态多样性在某些辐射中不一定是适应性的。
