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.精细尺度减数分裂重组图谱（fine scale meiotic recombination maps）已揭示诸多物种基因组内交换率（crossover rate）存在大量变异，其中哺乳动物与酵母基因组中的这类变异集中于重组率较背景水平升高10~100倍的<5千碱基（kb）区域，这类区域被称为“重组热点（hotspots）”。果蝇全基因组呈现显著的重组率异质性，但目前尚未发现这类高度定位化重组热点的相关证据。本研究对拟暗果蝇（Drosophila pseudoobscura）2号染色体上一段40 kb的区域开展重组率检测：其中一段20 kb的区间以每5 kb为间隔进行采样分析，相邻的另一段20 kb区间则被均分为两段10 kb的片段进行检测。研究发现，该40 kb区域内的重组事件在各5 kb和10 kb的检测区间中呈相对均匀分布，而非集中于单个5 kb区域内。结合其他近期研究成果，这一结果表明果蝇的重组格局可能与多数哺乳动物和酵母中观察到的点状重组模式存在差异。此外，本研究未在20 kb区间内发现平均成对核苷酸多样性（average pairwise nucleotide diversity）与序列分化程度同重组率之间存在相关性，同时也未观察到以周为单位统计的母龄对样本中重组率存在任何影响。