全基因组重复也称为基因组多倍化，通过加倍染色体的数量产生大量的重复基因，为新基因功能的产生提供了进化上的潜力。 十字花科是进化上比较成功的被子植物类群，它既包含模式植物拟南芥和多种重要作物，也包含3000多种具有广泛地理分布的植物。十字花科祖先曾经发生过多次多倍化事件，因此为研究多倍化促进增加生物多样性的分子机制提供了良好材料。 我们将使用多种组学分析和系统发育基因组学方法研究十字花科多倍化导致的基因组复杂性和动态变化，包括：十字花科各类群进化过程中重复基因保留、丢失和功能分化；使用转录组方法研究重复基因的协同进化模式，揭示耐盐机制在各物种间的共性与特性；比较十字花科物种的DNA甲基化状态，探索多倍化导致的DNA甲基化短期固化特征和长期动态规律。本项目将从基因组进化、转录调控网络和表观修饰变化角度入手研究多倍化重复基因的新功能化、亚功能化，为揭示多倍化驱动生殖隔离和物种分化提供分子证据。

Whole genome duplication (WGD) or polyploidization doubles the chromosomes initially and results in hundreds to thousands of retained gene duplicates, which provide evolutionary potentials for generating novel functions. Brassicaceae is the most successful group of angiosperms, containing more than 3,000 species, with many important agricultural and economical crops that have undergone both ancient WGDs and recent ones, thus providing excellent materials for investigating the mechanisms of species diversification promoted by polyploidization. We will perform comparative genomic and phylogenomic anlyases on multiple Brassicaceae genomes to detect genomic content dynamics, which leads to the increasing complexities of genomic contents. In details, the project will a) investigate the retention or loss of gene duplicates as well as their functional divergence in Brassicaceae; b) reveal the patterns of co-evolution for gene duplicates relating to salt response by transcriptomic sequencing and analyses; c) compare the status of DNA methylation among multiple species to discover DNA methylation changes fixed immediately after polyploidization and the novel changes during the evolution of Brassicaceae. Such studies will provide molecular clues for understanding productive isolation and species diversification driven by polyploidization in the angels of genomic evolution, transcriptional regulatory network and epigenetic modifications.