Largely unlinked gene sets targeted by selection for domestication syndrome phenotypes in maize and sorghum

The domestication of diverse grain crops from wild grasses was a result of artificial selection (人工选择) for a suite of (一系列) overlapping traits producing changes referred to in aggregate (合计) as ‘domestication syndrome 驯化综合特征’. Parallel phenotypic change can be accomplished by either selection on orthologous genes or selection on non-orthologous genes with parallel phenotypic effects. To determine how often artificial selection for domestication traits in the grasses targeted orthologous genes, we employed resequencing data from wild and domesticated accessions of Zea (maize) and Sorghum (sorghum). Many ‘classic’ domestication genes identified through quantitative trait locus mapping (数量性状位点作图) in populations resulting from wild/domesticated crosses indeed show signatures of parallel selection in both maize and sorghum. However, the overall number of genes showing signatures of parallel selection in both species is not significantly different from that expected by chance. This suggests that while a small number of genes will extremely large phenotypic effects have been targeted repeatedly by artificial selection during domestication, the optimization part of domestication targeted small and largely non-overlapping subsets of all possible genes which could produce equivalent (等效的) phenotypic alterations.

不同谷类作物从野草的驯化是对一系列重合的性状进行人工选择所引起的表型的改变，统称为驯化综合特征。类似表型的改变可以通过对同源基因或者具有类似表型效应的非同源基因的选择获得。为了研究在草本驯化过程中人工选择对于同源基因的频率，本文基于玉米和高粱各自野生型和驯化种进行重测序研究。通过对野生型和驯化种杂交群体进行数量性状位点作图所鉴定的“经典的”驯化基因确实在玉米和高粱种显示出平衡选择的特征。然而，在这两个物种中显示平衡选择的基因总数与随机情况下的期望值不存在显著差异。这说明当一小部分对于表型具有非常大的影响的基因在驯化过程中被人工选择反复的进行选择，最优组合的驯化是直接靶向小的、非重叠的，并且对于表型具有等效改变的所有可能的基因子集。

通讯：James C. Schnable (https://agronomy.unl.edu/schnable)

个人简介：2008年，康奈尔大学，生物学学士；2012年，加州大学伯克利分校，植物生物学博士。

doi: 10.1111/tpj.13806