Ancestral polyploidy in seed plants and angiosperms

Whole-genome duplication (WGD), or polyploidy, followed by gene loss and diploidization has long been recognized as an important evolutionary force in animals, fungi and other organisms1, 2, 3, especially plants. The success of angiosperms has been attributed, in part, to innovations associated with gene or whole-genome duplications4, 5, 6, but evidence for proposed ancient genome duplications pre-dating the divergence of monocots and eudicots remains equivocal in analyses of conserved gene order. Here we use comprehensive phylogenomic analyses of sequenced plant genomes and more than 12.6 million new expressed-sequence-tag sequences from phylogenetically pivotal lineages to elucidate two groups of ancient gene duplications—one in the common ancestor of extant seed plants and the other in the common ancestor of extant angiosperms. Gene duplication events were intensely concentrated around 319 and 192 million years ago, implicating two WGDs in ancestral lineages shortly before the divers...

全基因组复制（whole-genome duplication, WGD，亦称多倍体化）后伴随基因丢失与二倍体化，长期以来被视作动物、真菌及其他生物¹,²,³的重要进化动力，尤以植物为甚。被子植物（angiosperms）的演化成功，部分归因于与基因复制或全基因组复制相关的创新事件⁴,⁵,⁶；但在基于保守基因顺序的分析中，针对单子叶植物（monocots）与真双子叶植物（eudicots）分化前的古老基因组复制假说，相关证据仍不明确。本研究通过对已测序植物基因组的全面系统发育基因组学分析，以及来自系统发育关键类群的逾1260万条全新表达序列标签（expressed sequence tag, EST）序列，阐明了两类古老基因复制事件：一类发生于现存种子植物的共同祖先，另一类则发生于现存被子植物的共同祖先。基因复制事件高度集中于约3.19亿年和1.92亿年前，暗示在……发生前不久的祖先类群中存在两次全基因组复制事件。