Stern D L
University Museum of Zoology, Department of Zoology, University of Cambridge, United Kingdom.
Evolution. 2000 Aug;54(4):1079-91. doi: 10.1111/j.0014-3820.2000.tb00544.x.
One of the oldest problems in evolutionary biology remains largely unsolved. Which mutations generate evolutionarily relevant phenotypic variation? What kinds of molecular changes do they entail? What are the phenotypic magnitudes, frequencies of origin, and pleiotropic effects of such mutations? How is the genome constructed to allow the observed abundance of phenotypic diversity? Historically, the neo-Darwinian synthesizers stressed the predominance of micromutations in evolution, whereas others noted the similarities between some dramatic mutations and evolutionary transitions to argue for macromutationism. Arguments on both sides have been biased by misconceptions of the developmental effects of mutations. For example, the traditional view that mutations of important developmental genes always have large pleiotropic effects can now be seen to be a conclusion drawn from observations of a small class of mutations with dramatic effects. It is possible that some mutations, for example, those in cis-regulatory DNA, have few or no pleiotropic effects and may be the predominant source of morphological evolution. In contrast, mutations causing dramatic phenotypic effects, although superficially similar to hypothesized evolutionary transitions, are unlikely to fairly represent the true path of evolution. Recent developmental studies of gene function provide a new way of conceptualizing and studying variation that contrasts with the traditional genetic view that was incorporated into neo-Darwinian theory and population genetics. This new approach in developmental biology is as important for microevolutionary studies as the actual results from recent evolutionary developmental studies. In particular, this approach will assist in the task of identifying the specific mutations generating phenotypic variation and elucidating how they alter gene function. These data will provide the current missing link between molecular and phenotypic variation in natural populations.
进化生物学中最古老的问题之一在很大程度上仍未得到解决。哪些突变产生了与进化相关的表型变异？它们会引发哪些分子变化？这些突变的表型幅度、起源频率和多效性效应是什么？基因组是如何构建的，以允许观察到的丰富表型多样性？从历史上看，新达尔文主义的综合者强调微突变在进化中的主导地位，而其他人则注意到一些显著突变与进化转变之间的相似性，从而支持大突变主义。双方的论点都因对突变发育效应的误解而存在偏差。例如，传统观点认为重要发育基因的突变总是具有很大的多效性效应，现在可以看出这是从一小类具有显著效应的突变观察中得出的结论。例如，某些突变，如顺式调控DNA中的突变，可能很少或没有多效性效应，并且可能是形态进化的主要来源。相比之下，导致显著表型效应的突变，尽管表面上与假设的进化转变相似，但不太可能公平地代表进化的真实路径。最近对基因功能的发育研究提供了一种与传统遗传学观点不同的概念化和研究变异的新方法，传统遗传学观点已被纳入新达尔文主义理论和群体遗传学。发育生物学中的这种新方法对微进化研究的重要性与最近进化发育研究的实际结果一样重要。特别是，这种方法将有助于识别产生表型变异的特定突变，并阐明它们如何改变基因功能。这些数据将提供目前自然种群中分子变异和表型变异之间缺失的环节。
