Rowan et al. generated a dataset of over 17,000 meiotic crossovers (COs) from over 2000 F2 individuals from a single Arabidopsis thaliana cross. The unprecedented density of COs and the high-quality reference genomes of the two... Many environmental, genetic, and epigenetic factors are known to affect the frequency and positioning of meiotic crossovers (COs). Suppression of COs by large, cytologically visible inversions and translocations has long been recognized, but relatively little is known about how smaller structural variants (SVs) affect COs. To examine fine-scale determinants of the CO landscape, including SVs, we used a rapid, cost-effective method for high-throughput sequencing to generate a precise map of >17,000 COs between the Col-0 and Ler-0 accessions of Arabidopsis thaliana. COs were generally suppressed in regions with SVs, but this effect did not depend on the size of the variant region, and was only marginally affected by the variant type. CO suppression did not extend far beyond the SV borders and CO rates were slightly elevated in the flanking regions. Disease resistance gene clusters, which often exist as SVs, exhibited high CO rates at some loci, but there was a tendency toward depressed CO rates at loci where large structural differences exist between the two parents. Our high-density map also revealed in fine detail how CO positioning relates to genetic (DNA motifs) and epigenetic (chromatin structure) features of the genome. We conclude that suppression of COs occurs over a narrow region spanning large- and small-scale SVs, representing an influence on the CO landscape in addition to sequence and epigenetic variation along chromosomes.

中文翻译：

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超高密度拟南芥交叉图谱，细化结构变异和表观遗传特征的影响。

罗文等人。生成了来自单个拟南芥杂交的 2000 多个 F2 个体的 17,000 多个减数分裂交叉 (CO) 的数据集。CO 的前所未有的密度和两者的高质量参考基因组......已知许多环境、遗传和表观遗传因素会影响减数分裂交叉 (CO) 的频率和定位。人们早已认识到细胞学上可见的大倒位和易位对 CO 的抑制作用，但对于较小的结构变异 (SV) 如何影响 CO 知之甚少。为了研究 CO 景观（包括 SV）的精细尺度决定因素，我们使用了一种快速、经济高效的高通量测序方法，在拟南芥 Col-0 和 Ler-0 种质之间生成了超过 17,000 个 CO 的精确图谱。CO 通常在有 SV 的区域受到抑制，但这种效应并不取决于变异区域的大小，并且仅受变异类型的轻微影响。CO 抑制并未超出 SV 边界，并且侧翼区域的 CO 浓度略有升高。抗病基因簇通常以 SV 形式存在，在某些位点表现出较高的 CO 率，但在两个亲本之间存在较大结构差异的位点存在降低 CO 率的趋势。我们的高密度图还详细揭示了 CO 定位如何与基因组的遗传（DNA 基序）和表观遗传（染色质结构）特征相关。我们得出的结论是，CO 的抑制发生在跨越大型和小规模 SV 的狭窄区域，除了沿染色体的序列和表观遗传变异外，还代表着对 CO 景观的影响。