BackgroundWhole-genome duplications (WGDs) have dominated the evolutionary history of plants. One consequence of WGD is a dramatic restructuring of the genome as it undergoes diploidization, a process under which deletions and rearrangements of various sizes scramble the genetic material, leading to a repacking of the genome and eventual return to diploidy. Here, we investigate the history of WGD in the columbine genus Aquilegia, a basal eudicot, and use it to illuminate the origins of the core eudicots.ResultsWithin-genome synteny confirms that columbines are ancient tetraploids, and comparison with the grape genome reveals that this tetraploidy appears to be shared with the core eudicots. Thus, the ancient gamma hexaploidy found in all core eudicots must have involved a two-step process: first, tetraploidy in the ancestry of all eudicots, then hexaploidy in the ancestry of core eudicots. Furthermore, the precise pattern of synteny sharing suggests that the latter involved allopolyploidization and that core eudicots thus have a hybrid origin.ConclusionsNovel analyses of synteny sharing together with the well-preserved structure of the columbine genome reveal that the gamma hexaploidy at the root of core eudicots is likely a result of hybridization between a tetraploid and a diploid species.

中文翻译：

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Aquilegia 基因组揭示了核心真双子叶植物的杂交起源

背景全基因组重复（WGD）主导了植物的进化史。WGD 的一个后果是基因组在经历二倍体化时发生了戏剧性的重组，在这个过程中，各种大小的缺失和重排扰乱了遗传物质，导致基因组重新包装并最终返回二倍体。在这里，我们研究了鸽属 Aquilegia（一种基础真双子叶植物）中 WGD 的历史，并用它来阐明核心真双子叶植物的起源。四倍体似乎与核心真双子叶植物共享。因此，在所有核心真双子叶植物中发现的古代伽马六倍体必须涉及两个步骤：首先，所有真双子叶植物祖先中的四倍体，然后是核心真双子叶植物祖先的六倍体。此外，同线性共享的精确模式表明后者涉及异源多倍体化，因此核心真双子叶植物具有杂交起源。 eudicots 可能是四倍体和二倍体物种之间杂交的结果。