Cold tolerance, the ability to cope with low temperature stress, is a critical adaptation in thermally variable environments. An individual's cold tolerance comprises several traits including minimum temperatures for growth and activity, ability to survive severe cold, and ability to resume normal function after cold subsides. Across species, these traits are correlated, suggesting they were shaped by shared evolutionary processes or possibly share physiological mechanisms. However, the extent to which cold tolerance traits and their associated mechanisms covary within populations has not been assessed. We measured five cold tolerance traits—critical thermal minimum, chill coma recovery, short‐ and long‐term cold tolerance, and cold‐induced changes in locomotor behavior—along with cold‐induced expression of two genes with possible roles in cold tolerance (heat shock protein 70 and frost)—across 12 lines of Drosophila melanogaster derived from a single population. We observed significant genetic variation in all traits, but few were correlated across genotypes, and these correlations were sex‐specific. Further, cold‐induced gene expression varied by genotype, but there was no evidence supporting our hypothesis that cold‐hardy lines would have either higher baseline expression or induction of stress genes. These results suggest cold tolerance traits possess unique mechanisms and have the capacity to evolve independently.

中文翻译：

---

不同基因型的黑腹果蝇不同的耐寒性状独立变化

耐寒性，即应对低温压力的能力，是热变环境中的关键适应性。一个人的耐寒性包括几个特征，包括生长和活动的最低温度、在严寒中生存的能力以及在寒冷消退后恢复正常功能的能力。在物种之间，这些特征是相关的，表明它们是由共同的进化过程或可能共同的生理机制塑造的。然而，尚未评估冷耐受性状及其相关机制在种群内的共变程度。我们测量了五个耐寒性状——临界热最小值、冷昏迷恢复、短期和长期耐寒性、在来自单一种群的 12 种黑腹果蝇品系中，冷诱导的运动行为变化——以及冷诱导的两个基因的表达，这些基因可能在耐寒中发挥作用（热休克蛋白 70 和霜冻）。我们观察到所有性状的显着遗传变异，但很少有跨基因型相关的，而且这些相关性是性别特异性的。此外，寒冷诱导的基因表达因基因型而异，但没有证据支持我们的假设，即耐寒品系将具有更高的基线表达或诱导应激基因。这些结果表明耐寒性状具有独特的机制并具有独立进化的能力。我们观察到所有性状的显着遗传变异，但很少有跨基因型相关的，而且这些相关性是性别特异性的。此外，寒冷诱导的基因表达因基因型而异，但没有证据支持我们的假设，即耐寒品系将具有更高的基线表达或诱导应激基因。这些结果表明耐寒性状具有独特的机制并具有独立进化的能力。我们观察到所有性状的显着遗传变异，但很少有跨基因型相关的，而且这些相关性是性别特异性的。此外，寒冷诱导的基因表达因基因型而异，但没有证据支持我们的假设，即耐寒品系将具有更高的基线表达或诱导应激基因。这些结果表明耐寒性状具有独特的机制并具有独立进化的能力。