AgroParisTech, UMR 0320/UMR 8120 Génétique Végétale, F-91190 Gif-sur-Yvette, France.
Evolution. 2010 Jul;64(7):2110-25. doi: 10.1111/j.1558-5646.2010.00970.x. Epub 2010 Feb 9.
In annual plant species, flowering time is a major adaptive trait that synchronizes the initiation of reproduction with favorable environmental conditions. Here, we aimed at studying the evolution of flowering time in three experimental populations of bread wheat, grown in contrasting environments (Northern to Southern France) for 12 generations. By comparing the distribution of phenotypic and presumably neutral variation, we first showed that flowering time responded to selection during the 12 generations of the experiment. To get insight into the genetic architecture of that trait, we then tested whether the distribution of genetic polymorphisms at six candidate genes, presumably involved in the trait expression, departed from neutral expectation. To that end, we focused on the temporal variation during the course of the experiment, and on the spatial differentiation at the end of the experiment, using previously published methods adapted to our experimental design. Only those genes that were strongly associated with flowering time variation were detected as responding to selection. For genes that had low-to-moderate phenotypic effects, or when there was interaction across different genes, we did not find evidence of selection using methods based on the distribution of temporal or spatial variation. In such cases, it might be more informative to consider multilocus and multiallelic combinations across genes, which could be the targets of selection.
在一年生植物物种中，开花时间是一个主要的适应性特征，它使繁殖的开始与有利的环境条件同步。在这里，我们旨在研究三种实验性小麦种群的开花时间进化，这些种群在 12 个世代中生长在不同的环境中（从法国北部到南部）。通过比较表型和假定中性变异的分布，我们首先表明，在实验的 12 个世代中，开花时间受到了选择的影响。为了深入了解该性状的遗传结构，我们随后测试了六个候选基因中的遗传多态性分布是否偏离了中性预期。为此，我们专注于实验过程中的时间变化，以及实验结束时的空间分化，使用了先前发表的适应我们实验设计的方法。只有那些与开花时间变化强烈相关的基因被检测到受到选择的影响。对于那些具有低至中等表型效应的基因，或者当不同基因之间存在相互作用时，我们没有使用基于时间或空间变化分布的方法发现选择的证据。在这种情况下，考虑跨基因的多基因和多等位基因组合可能更能提供信息，这些组合可能是选择的目标。
