The commercial strawberry, Fragaria × ananassa, is a recent allo-octoploid that is cultivated worldwide. However, other than F. vesca, which is universally accepted one of its diploid ancestors, its other early diploid progenitors remain unclear. Here, we performed comparative analyses of the genomes of five diploid strawberries, F. iinumae, F. vesca, F. nilgerrensis, F. nubicola, and F. viridis, of which the latter three are newly sequenced. We found that the genomes of these species share highly conserved gene content and gene order. Using an alignment-based approach, we show that F. iinumae and F. vesca are the diploid progenitors to the octoploid F. × ananassa, whereas the other three diploids that we analyzed in this study are not parental species. We generated a fully resolved, dated phylogeny of Fragaria and determined that the genus arose ca. 6.37 million years ago. Our results effectively resolve conflicting hypotheses regarding the putative diploid progenitors of the cultivated strawberry, establish a reliable backbone phylogeny for the genus, and provide genetic resources for molecular breeding.

中文翻译：

---

追踪栽培八倍体草莓的二倍体祖先。

商业草莓Fragaria × ananassa是一种在世界范围内种植的近来异种八倍体。但是，除了被广泛接受的F. vesca二倍体祖先之一，其他早期二倍体祖细胞仍不清楚。在这里，我们进行了五个二倍体草莓的基因组比较分析F. iinumae，F. vesca，F. nilgerrensis，F. nubicola和F.贻贝，其中后三个新测序。我们发现这些物种的基因组共享高度保守的基因含量和基因顺序。使用基于比对的方法，我们表明F. iinumaeF.和vesca是八倍体F. × ananassa的二倍体祖细胞，而我们在本研究中分析的其他三个二倍体不是亲本。我们生成了一个完全分解的，过时的草莓属系统发育树，并确定该属大约在大约一个月前出现了。637万年前。我们的结果有效地解决了有关栽培草莓的假定二倍体祖细胞的矛盾假设，为该属建立了可靠的主链系统发育，并为分子育种提供了遗传资源。