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The Aquilegia genome reveals a hybrid origin of core eudicots
First author: Gökçe Aköz; Affiliations: Gregor Mendel Institute (孟德爾研究所): Vienna, Austria
Corresponding author: Magnus Nordborg
Whole-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. Within-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. Novel 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.
全基因組複製事件主宰了植物的演化歷史。全基因組複製事件其中一個後果便是基因組在經歷二倍體化時發生了劇烈的重組，在此過程中，各種各樣的缺失和重排拼湊整個遺傳物質，最終導致基因組重新組合形成二倍體。本文中，作者研究了一個基礎雙子葉植物毛茛科耬鬥菜屬的全基因組複製歷史，並探討了核心雙子葉植物的起源。基因組內共線性分析確認了耬鬥菜是一個古老的四倍體，與葡萄基因組的共線性分析顯示該四倍化事件是與所有核心雙子葉植物共享的。因此，在所有核心雙子葉植物中所發現的古六倍化，即gamma事件包含了兩個過程：首先，所有雙子葉植物的祖先發生了一次古四倍化事件；而後所有核心雙子葉植物的祖先發生了古六倍化事件。此外，精確的共線性共享模式說明後面的那次全基因組加倍事件是異源多倍體化事件，因此核心雙子葉植物是雜合起源的。新的共線性分析以及結構相對保存完好的耬鬥菜基因組揭示了核心雙子葉祖先的gamma六倍化事件很有可能是一次四倍體和二倍體物種雜交的結果。
通訊：Magnus Nordborg (https://www.oeaw.ac.at/gmi/research/research-groups/magnus-nordborg/)
個人簡介：1989年，瑞典隆德大學；學士；1994年，美國史丹福大學，博士；1994-1997年，美國芝加哥大學，博士後。
研究方向：演化基因組學。
doi: https://doi.org/10.1186/s13059-019-1888-8
Journal: Genome Biology
Published date: November 28, 2019