Environmental seasonality is a potent evolutionary force, capable of maintaining polymorphism, promoting phenotypic plasticity and causing bet-hedging. In Drosophila, environmental seasonality has been reported to affect life-history traits, tolerance to abiotic stressors and immunity. Oscillations in frequencies of alleles underlying fitness-related traits were also documented alongside SNPs across the genome. Here, we test for seasonal changes in two recombination characteristics, crossover rate and crossover interference, in a natural D. melanogaster population from India using morphological markers of the three major chromosomes. We show that winter flies, collected after the dry season, have significantly higher desiccation tolerance than their autumn counterparts. This difference proved to hold also for hybrids with three independent marker stocks, suggesting its genetic rather than plastic nature. Significant between-season changes are documented for crossover rate (in 9 of 13 studied intervals) and crossover interference (in four of eight studied pairs of intervals); both single and double crossovers were usually more frequent in the winter cohort. The winter flies also display weaker plasticity of both recombination characteristics to desiccation. We ascribe the observed differences to indirect selection on recombination caused by directional selection on desiccation tolerance. Our findings suggest that changes in recombination characteristics can arise even after a short period of seasonal adaptation (~8–10 generations).

环境季节性是一种强大的进化力量，能够维持多态性、促进表型可塑性并引起对冲。据报道，在果蝇中，环境季节性会影响生活史特征、对非生物应激源的耐受性和免疫力。与健康相关性状相关的等位基因频率的波动也与整个基因组中的 SNP 一起被记录下来。在这里，我们使用三个主要染色体的形态标记测试了来自印度的天然黑腹果蝇种群中两个重组特征（交叉率和交叉干扰）的季节变化。我们发现，干燥季节后收集的冬季果蝇比秋季果蝇具有显着更高的干燥耐受性。事实证明，这种差异也适用于具有三个独立标记种群的杂交品种，表明其遗传性质而非塑料性质。记录了交叉率（13 个研究间隔中的 9 个）和交叉干扰（8 个研究间隔中的 4 个）的显着季节间变化；在冬季队列中，单交换和双交换通常更频繁。冬季果蝇对干燥的重组特性也表现出较弱的可塑性。我们将观察到的差异归因于干燥耐受性的定向选择引起的重组的间接选择。我们的研究结果表明，即使经过短期的季节性适应（约 8-10 代），重组特征也可能发生变化。