Buxus and Tetracentron genomes

Ancient whole-genome duplications (WGDs) characterize many large clades of angiosperms, including angiosperms themselves. Prominently, the core eudicot clade accommodates 70% of all angiosperms and shares ancestral hexaploidy, termed gamma. Gamma arose via two WGDs that occurred early in eudicot history; however, the relative timing of these is unclear, largely due to the lack of high-quality genomes among early-diverging eudicots. We provide complete genomes for Buxus sinica (Buxales) and Tetracentron sinense (Trochodendrales), representing the lineages most closely related to core eudicots. We show that Buxus and Tetracentron are both characterized by independent WGDs, resolve relationships among early-diverging eudicots and their respective genomes, and use a new pipeline (RACCROCHE) to reconstruct ancestral genome structure at three key phylogenetic nodes of eudicot diversification. Our reconstructions indicate genome structure remained relatively stable during early eudicot diversi...

全基因组复制（whole-genome duplications, WGDs）是被子植物多个大型演化支的典型特征，被子植物本身亦具有该特征。其中，核心真双子叶植物演化支囊括了70%的被子植物物种，其共同祖先发生了被称为γ（gamma）的祖先六倍化事件。γ事件起源于真双子叶植物演化早期的两次全基因组复制事件，但二者的相对发生时间仍不明确，这主要是由于早期分化真双子叶植物类群中缺乏高质量基因组数据。本研究提供了黄杨目（Buxales）小叶黄杨（Buxus sinica）与昆栏树目（Trochodendrales）连香树（Tetracentron sinense）的完整基因组，二者均为与核心真双子叶植物亲缘关系最近的类群。研究表明，小叶黄杨与连香树均发生了独立的全基因组复制事件；我们解析了早期分化真双子叶植物类群及其各自基因组间的演化关系，并采用全新的RACCROCHE分析流程，重构了真双子叶植物分化过程中三个关键系统发育节点的祖先基因组结构。我们的重构结果显示，在真双子叶植物早期分化阶段，基因组结构保持了相对稳定……