Unité Mixte de Recherche (UMR) 6553 - ECOBIO (Ecosystems, Biodiversity, Evolution), University of Rennes, CNRS, Rennes, France.
Department of Ecology and Genetics, Evolutionary Biology Center and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
Mol Biol Evol. 2024 Sep 4;41(9). doi: 10.1093/molbev/msae183.
During the meiosis of many eukaryote species, crossovers tend to occur within narrow regions called recombination hotspots. In plants, it is generally thought that gene regulatory sequences, especially promoters and 5' to 3' untranslated regions, are enriched in hotspots, but this has been characterized in a handful of species only. We also lack a clear description of fine-scale variation in recombination rates within genic regions and little is known about hotspot position and intensity in plants. To address this question, we constructed fine-scale recombination maps from genetic polymorphism data and inferred recombination hotspots in 11 plant species. We detected gradients of recombination in genic regions in most species, yet gradients varied in intensity and shape depending on specific hotspot locations and gene structure. To further characterize recombination gradients, we decomposed them according to gene structure by rank and number of exons. We generalized the previously observed pattern that recombination hotspots are organized around the boundaries of coding sequences, especially 5' promoters. However, our results also provided new insight into the relative importance of the 3' end of genes in some species and the possible location of hotspots away from genic regions in some species. Variation among species seemed driven more by hotspot location among and within genes than by differences in size or intensity among species. Our results shed light on the variation in recombination rates at a very fine scale, revealing the diversity and complexity of genic recombination gradients emerging from the interaction between hotspot location and gene structure.
在许多真核生物物种的减数分裂过程中，交叉往往发生在称为重组热点的狭窄区域内。在植物中，人们普遍认为基因调控序列，特别是启动子和 5' 到 3' 非翻译区，在热点中富集，但这仅在少数几种物种中得到了描述。我们还缺乏对基因区域内重组率的精细变化的清晰描述，并且对植物中的热点位置和强度知之甚少。为了解决这个问题，我们从遗传多态性数据构建了精细的重组图谱，并推断了 11 种植物物种中的重组热点。我们在大多数物种中检测到基因区域中的重组梯度，但梯度的强度和形状取决于特定的热点位置和基因结构。为了进一步描述重组梯度，我们根据基因结构按秩和外显子数量进行了分解。我们概括了先前观察到的模式，即重组热点围绕编码序列的边界组织，特别是 5' 启动子。然而，我们的结果还提供了新的见解，即基因的 3' 端在某些物种中的相对重要性，以及在某些物种中热点可能远离基因区域的位置。物种之间的差异似乎更多地是由基因内和基因间的热点位置驱动，而不是由物种之间的大小或强度差异驱动。我们的结果揭示了非常精细的重组率变化，揭示了热点位置和基因结构相互作用产生的基因重组梯度的多样性和复杂性。
