Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
Genetics. 2011 Jan;187(1):271-87. doi: 10.1534/genetics.110.121327. Epub 2010 Oct 13.
Determining the identity and distribution of molecular changes leading to the evolution of modern crop species provides major insights into the timing and nature of historical forces involved in rapid phenotypic evolution. In this study, we employed an integrated candidate gene strategy to identify loci involved in the evolution of flowering time during early domestication and modern improvement of the sunflower (Helianthus annuus). Sunflower homologs of many genes with known functions in flowering time were isolated and cataloged. Then, colocalization with previously mapped quantitative trait loci (QTLs), expression, or protein sequence differences between wild and domesticated sunflower, and molecular evolutionary signatures of selective sweeps were applied as step-wise criteria for narrowing down an original pool of 30 candidates. This process led to the discovery that five paralogs in the flowering locus T/terminal flower 1 gene family experienced selective sweeps during the evolution of cultivated sunflower and may be the causal loci underlying flowering time QTLs. Our findings suggest that gene duplication fosters evolutionary innovation and that natural variation in both coding and regulatory sequences of these paralogs responded to a complex history of artificial selection on flowering time during the evolution of cultivated sunflower.
确定导致现代作物物种进化的分子变化的身份和分布，为了解涉及快速表型进化的历史力量的时间和性质提供了主要的见解。在这项研究中，我们采用了综合候选基因策略来鉴定在向日葵（Helianthus annuus）早期驯化和现代改良过程中开花时间进化过程中涉及的基因座。许多与开花时间已知功能的基因在向日葵中的同源物被分离并编目。然后，将与先前映射的数量性状基因座（QTL）的共定位、野生和驯化向日葵之间的表达或蛋白质序列差异以及选择性清除的分子进化特征应用作为逐步标准，以缩小原始的 30 个候选基因库。这一过程导致发现，在栽培向日葵进化过程中，开花 locus T/terminal flower 1 基因家族的五个旁系同源物经历了选择性清除，并且可能是开花时间 QTL 的因果基因座。我们的研究结果表明，基因复制促进了进化创新，并且这些旁系同源物的编码和调节序列中的自然变异对栽培向日葵中开花时间的复杂人工选择历史做出了反应。
