Data from: How hot are Drosophila hotspots? Examining recombination rate variation and associations with nucleotide diversity, divergence, and maternal age in Drosophila pseudoobscura

Fine scale meiotic recombination maps have uncovered a large amount of variation in crossover rate across the genomes of many species, and such variation in mammalian and yeast genomes is concentrated to <5 kb regions of highly elevated recombination rates (10–100x the background rate) called “hotspots.” Drosophila exhibit substantial recombination rate heterogeneity across their genome, but evidence for these highly-localized hotspots is lacking. We assayed recombination across a 40 Kb region of Drosophila pseudoobscura chromosome 2, with one 20 kb interval assayed every 5 Kb and the adjacent 20 kb interval bisected into 10 kb pieces. We found that recombination events across the 40 kb stretch were relatively evenly distributed across each of the 5 kb and 10 kb intervals, rather than concentrated in a single 5 kb region. This, in combination with other recent work, indicates that the recombination landscape of Drosophila may differ from the punctate recombination pattern observed in many mammals and yeast. Additionally, we found no correlation of average pairwise nucleotide diversity and divergence with recombination rate across the 20 kb intervals, nor any effect of maternal age in weeks on recombination rate in our sample.

高精度减数分裂重组图谱（fine-scale meiotic recombination map）已在众多物种的基因组中揭示了大量交叉率变异；在哺乳动物与酵母基因组中，这类变异集中于重组率显著升高（为背景重组率的10~100倍）的<5千碱基对（kb）区域，即所谓“重组热点（hotspot）”。
果蝇基因组中存在显著的重组率异质性，但目前尚未发现这类高度局域化热点的相关证据。
本研究对拟暗果蝇（Drosophila pseudoobscura）2号染色体上一段40 kb的基因组区段进行了重组率检测：其中一段20 kb区间以每5 kb为间隔进行检测，相邻的另一段20 kb区间则被均分为两个10 kb的子区间。
我们发现，该40 kb区段内的重组事件在所有5 kb和10 kb子区间中均呈相对均匀分布，而非集中于单个5 kb区域。结合其他近期研究成果，这一结果表明果蝇的重组景观（recombination landscape）可能与多数哺乳动物和酵母所呈现的点状重组模式存在差异。
此外，本研究未发现20 kb区间内的平均成对核苷酸多样性与序列分歧度和重组率存在相关性，也未观察到以周为单位的母本年龄对重组率的影响。