Features of the Arabidopsis recombination landscape resulting from the combined loss of sequence variation and DNA methylation
Features of the Arabidopsis recombination landscape resulting from the combined loss of sequence variation and DNA methylation
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DOI：
10.1073/pnas.1212955109
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发表时间：
2012-10-02
影响因子：
11.1
通讯作者：
Johannes, Frank
中科院分区：
文献类型：
--
作者：
Colome-Tatche, Maria;Cortijo, Sandra;Johannes, Frank
减数分裂交换（CO）的速率沿染色体沿着变化很大，导致物理距离和遗传距离之间的显着扭曲。这种变异背后的原因正在被解开，DNA序列和染色质状态已成为关键因素。然而，在何种程度上的重复丰富的植物和哺乳动物染色体的近着丝粒区域内的CO的抑制结果从其高水平的DNA多态性和异染色质状态，特别是其密集的DNA甲基化，仍然是未知的。在这里，我们测试了去除序列多态性和重复相关的DNA甲基化对拟南芥定位群体减数分裂重组景观的综合影响。为了做到这一点，我们使用全基因组DNA甲基化数据从一个大的面板的等基因表观遗传重组近交系（epiRILs），以获得一个重组图的基础上126减数分裂稳定，差异甲基化区域覆盖81.9%的基因组。我们证明，在这个实验环境中，染色体的着丝粒周围区域内的CO的抑制持续存在。此外，抑制增强内3-Mb区域侧翼pericentromeric边界，这种影响似乎是由染色体臂中的重组活性增加补偿。与17个经典拟南芥杂交的直接比较表明，这些重组变化将epiRILs置于自然变异范围的边界，但并不严重到足以显著超越该边界。考虑到这一群体代表了一个极端，关键重组障碍已被强制降至最低，这种稳健性水平是显着的。
The rate of meiotic crossing over (CO) varies considerably along chromosomes, leading to marked distortions between physical and genetic distances. The causes underlying this variation are being unraveled, and DNA sequence and chromatin states have emerged as key factors. However, the extent to which the suppression of COs within the repeat-rich pericentromeric regions of plant and mammalian chromosomes results from their high level of DNA polymorphisms and from their heterochromatic state, notably their dense DNA methylation, remains unknown. Here, we test the combined effect of removing sequence polymorphisms and repeat-associated DNA methylation on the meiotic recombination landscape of an Arabidopsis mapping population. To do so, we use genome-wide DNA methylation data from a large panel of isogenic epigenetic recombinant inbred lines (epiRILs) to derive a recombination map based on 126 meiotically stable, differentially methylated regions covering 81.9% of the genome. We demonstrate that the suppression of COs within pericentromeric regions of chromosomes persists in this experimental setting. Moreover, suppression is reinforced within 3-Mb regions flanking pericentromeric boundaries, and this effect appears to be compensated by increased recombination activity in chromosome arms. A direct comparison with 17 classical Arabidopsis crosses shows that these recombination changes place the epiRILs at the boundary of the range of natural variation but are not severe enough to transgress that boundary significantly. This level of robustness is remarkable, considering that this population represents an extreme with key recombination barriers having been forced to a minimum.