Abstract：
Cultivated spinach (Spinacia oleracea) is a dioecious species. We report high-quality genome sequences for its two closest wild relatives, Spinacia turkestanica and Spinacia tetrandra, which are also dioecious, and are used to study the genetics of spinach domestication. Using a combination of genomic approaches, we assembled genomes of both these species and analyzed them in comparison with the previously assembled S. oleracea genome. These species diverged c. 6.3 million years ago (Ma), while cultivated spinach split from S. turkestanica 0.8 Ma. In all three species, all six chromosomes include very large gene-poor, repeat-rich regions, which, in S. oleracea, are pericentromeric regions with very low recombination rates in both male and female genetic maps. We describe population genomic evidence that the similar regions in the wild species also recombine rarely. We characterized 282 structural variants (SVs) that have been selected during domestication. These regions include genes associated with leaf margin type and flowering time. We also describe evidence that the downy mildew resistance loci of cultivated spinach are derived from introgression from both wild spinach species. Collectively, this study reveals the genome architecture of spinach assemblies and highlights the importance of SVs during the domestication of cultivated spinach.
摘要：
栽培菠菜（Spinaciaoleracea）是雌雄异株。我们报告了其两个最接近的野生近亲的高质量基因组序列，土耳其刺槐和西班牙刺槐，它们也是雌雄异株的，并用于研究菠菜驯化的遗传学。使用基因组方法的组合，我们组装了这两个物种的基因组，并与以前组装的S.oleracea基因组进行了比较分析。这些物种在630万年前（Ma），而栽培的菠菜从土耳其S.turkestanica分裂0.8Ma。在所有三个物种中，所有六个染色体包括非常大的基因贫乏，重复丰富的区域，which,在S.oleracea，是雄性和雌性基因图谱中重组率非常低的着丝粒区域。我们描述了种群基因组证据，表明野生物种中的相似区域也很少重组。我们鉴定了在驯化过程中选择的282种结构变体（SV）。这些区域包括与叶缘类型和开花时间相关的基因。我们还描述了证据表明，栽培菠菜的霜霉病抗性基因座来自两种野生菠菜物种的渗入。总的来说，这项研究揭示了菠菜装配的基因组结构，并强调了SVs在栽培菠菜驯化过程中的重要性。
