Natural selection shapes variation in genome-wide recombination rate in Drosophila pseudoobscura

While recombination is widely recognized to be a key modulator of numerous evolutionary phenomena, we have a poor understanding of how recombination rate itself varies and evolves within a species. Here, we performed a comprehensive study of recombination rate (rate of meiotic crossing over) in two natural populations of Drosophila pseudoobscura from Utah and Arizona, USA. We used an amplicon sequencing approach to obtain high-quality genotypes in approximately 8000 individual backcrossed offspring (17 mapping populations with roughly 530 individuals each), for which we then quantified crossovers. Interestingly, variation in recombination rate within and between populations largely manifested as differences in genome-wide recombination rate rather than remodeling of the local recombination landscape. Comparing populations, we discovered individuals from the Utah population displayed on average 8% higher crossover rates than the Arizona population, a statistically significant difference....尽管重组（recombination）被广泛认为是诸多进化现象的关键调控因子，但我们对重组速率本身在物种内的变化与演化机制仍知之甚少。本研究针对美国犹他州与亚利桑那州的两个自然伪暗果蝇（Drosophila pseudoobscura）种群，开展了重组速率（即减数分裂交换率）的综合研究。我们采用扩增子测序（amplicon sequencing）技术，对约8000个回交后代个体（分为17个作图群体，每个群体约含530个个体）获取了高质量基因型，并据此量化了染色体交换事件。值得注意的是，种群内部及种群间的重组速率差异，主要体现为全基因组重组速率的差异，而非局部重组景观的重塑。通过种群间对比，我们发现犹他州种群个体的平均交换率比亚利桑那州种群高出8%，该差异具有统计学显著性……