Whitehead Andrew, Crawford Douglas L
Louisiana State University, 202 Life Sciences Bldg. Baton Rouge, LA 70803, USA.
Mol Ecol. 2006 Apr;15(5):1197-211. doi: 10.1111/j.1365-294X.2006.02868.x.
Heritable variation in regulatory or coding regions is the raw material for evolutionary processes. The advent of microarrays has recently promoted examination of the extent of variation in gene expression within and among taxa and examination of the evolutionary processes affecting variation. This review examines these issues. We find: (i) microarray-based measures of gene expression are precise given appropriate experimental design; (ii) there is large inter-individual variation, which is composed of a minor nongenetic component and a large heritable component; (iii) variation among populations and species appears to be affected primarily by neutral drift and stabilizing selection, and to a lesser degree by directional selection; and (iv) neutral evolutionary divergence in gene expression becomes nonlinear with greater divergence times due to functional constraint. Evolutionary analyses of gene expression reviewed here provide unique insights into partitioning of regulatory variation in nature. However, common limitations of these studies include the tendency to assume a linear relationship between expression divergence and species divergence, and failure to test explicit hypotheses that involve the ecological context of evolutionary divergence.
调控区域或编码区域的可遗传变异是进化过程的原材料。微阵列技术的出现最近推动了对分类群内部和分类群之间基因表达变异程度的研究，以及对影响变异的进化过程的研究。本综述探讨了这些问题。我们发现：（i）在适当的实验设计下，基于微阵列的基因表达测量是精确的；（ii）存在较大的个体间变异，其由较小的非遗传成分和较大的可遗传成分组成；（iii）种群和物种之间的变异似乎主要受中性漂变和稳定选择的影响，而受定向选择的影响较小；（iv）由于功能限制，基因表达中的中性进化分歧在分歧时间较长时会变得非线性。本文综述的基因表达进化分析为自然界中调控变异的划分提供了独特的见解。然而，这些研究的常见局限性包括倾向于假设表达分歧与物种分歧之间存在线性关系，以及未能检验涉及进化分歧生态背景的明确假设。
