Meiotic recombination is a key biological process in plant evolution and breeding, as it generates genetic diversity in each generation through the formation of crossovers (COs). However, due to their importance in genome stability, COs are highly regulated in frequency and distribution. We previously demonstrated that this strict regulation of COs can be modified, both in terms of CO frequency and distribution, in allotriploid Brassica hybrids (2n = 3x = 29; AAC) resulting from a cross between Brassica napus (2n = 4x = 38; AACC) and Brassica rapa (2n = 2x = 20; AA). Using the recently updated B. napus genome now including pericentromeres, we demonstrated that COs occur in these cold regions in allotriploids, as close as 375 kb from the centromere. Reverse transcription quantitative PCR (RT-qPCR) of various meiotic genes indicated that Class I COs are likely involved in the increased recombination frequency observed in allotriploids. We also demonstrated that this modified recombination landscape can be maintained via successive generations of allotriploidy (odd ploidy level). This deregulated meiotic behavior reverts to strict regulation in allotetraploid (even ploidy level) progeny in the second generation. Overall, we provide an easy way to manipulate tight recombination control in a polyploid crop.

中文翻译：

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在偶数和奇数倍性水平之间交替打开和关闭重组控制，即使在着丝粒附近也是如此


减数分裂重组是植物进化和育种中的关键生物过程，因为它通过形成交叉 （CO） 在每一代中产生遗传多样性。然而，由于 CO 在基因组稳定性中的重要性，CO 的频率和分布受到高度调节。我们之前证明，在同种异体芸苔属杂交种 （2n = 3x = 29;AAC） 由 Brassica napus （2n = 4x = 38;AACC） 和 Brassica rapa （2n = 2x = 20;AA）。使用最近更新的 B. napus 基因组（现在包括着丝粒周围），我们证明了 CO 以同种异体三倍体的形式出现在这些寒冷地区，距离着丝粒最近 375 kb。各种减数分裂基因的逆转录定量 PCR （RT-qPCR） 表明，I 类 CO 可能与在同种异体三倍体中观察到的重组频率增加有关。我们还证明，这种修饰的重组景观可以通过连续的同种异体三倍体 （奇倍性水平） 来维持。这种失调的减数分裂行为在第二代的同种异体四倍体（甚至倍性水平）后代中恢复为严格调节。总体而言，我们提供了一种简单的方法来操纵多倍体作物中的严格重组控制。