Mandel Jennifer R, McAssey Edward V, Nambeesan Savithri, Garcia-Navarro Elena, Burke John M
Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America.
Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Córdoba, Spain.
PLoS One. 2014 Jun 10;9(6):e99620. doi: 10.1371/journal.pone.0099620. eCollection 2014.
Evolutionary analyses aimed at detecting the molecular signature of selection during crop domestication and/or improvement can be used to identify genes or genomic regions of likely agronomic importance. Here, we describe the DNA sequence-based characterization of a pool of candidate genes for crop-related traits in sunflower. These genes, which were identified based on homology to genes of known effect in other study systems, were initially sequenced from a panel of improved lines. All genes that exhibited a paucity of sequence diversity, consistent with the possible effects of selection during the evolution of cultivated sunflower, were then sequenced from a panel of wild sunflower accessions an outgroup. These data enabled formal tests for the effects of selection in shaping sequence diversity at these loci. When selection was detected, we further sequenced these genes from a panel of primitive landraces, thereby allowing us to investigate the likely timing of selection (i.e., domestication vs. improvement). We ultimately identified seven genes that exhibited the signature of positive selection during either domestication or improvement. Genetic mapping of a subset of these genes revealed co-localization between candidates for genes involved in the determination of flowering time, seed germination, plant growth/development, and branching and QTL that were previously identified for these traits in cultivated × wild sunflower mapping populations.
旨在检测作物驯化和/或改良过程中选择的分子特征的进化分析，可用于识别可能具有重要农艺价值的基因或基因组区域。在此，我们描述了基于DNA序列对向日葵中一组与作物相关性状的候选基因的特征分析。这些基因是基于与其他研究系统中已知效应基因的同源性鉴定出来的，最初是从一组改良品系中进行测序的。然后，从一组野生向日葵种质（一个外类群）中对所有表现出序列多样性匮乏的基因进行测序，这种匮乏与栽培向日葵进化过程中选择的可能效应一致。这些数据使得能够对这些位点上选择对序列多样性形成的影响进行正式检验。当检测到选择时，我们进一步从一组原始地方品种中对这些基因进行测序，从而使我们能够研究选择的可能时间（即驯化与改良）。我们最终鉴定出七个在驯化或改良过程中表现出正选择特征的基因。对这些基因的一个子集进行遗传图谱分析，揭示了参与开花时间、种子萌发、植物生长/发育和分枝决定的基因候选位点与之前在栽培×野生向日葵作图群体中针对这些性状鉴定出的QTL共定位。
