Long telomeres have become nearly synonymous with a variety of fitness-related traits and may be mediators of ecologically relevant variation in life history strategies. Growing evidence suggests that telomere dynamics are more predictive of performance than length itself, but very little work considers how telomere regulatory mechanisms respond to environmental challenges or influence performance in nature. Here, we combine observational and experimental datasets from free-living tree swallows (Tachycineta bicolor) to assess how performance is predicted by the telomere regulatory gene POT1, which encodes a shelterin protein that sterically blocks telomerase from repairing the telomere. First, we show that lower POT1 gene expression was associated with higher female quality, i.e. earlier breeding, and heavier body mass. We next challenged mothers with an immune stressor (lipopolysaccharide injection) that led to sickness in mothers and 24h of food restriction in their offspring. While POT1 did not respond to maternal injection, females with lower constitutive gene expression were better able to maintain feeding rates following treatment. Maternal injection also generated a one-day stressor for chicks, who responded with decreased POT1 gene expression and elongated telomeres. Other putatively stress-responsive mechanisms (i.e. glucocorticoids, antioxidants) were not significantly different between control and stress-exposed chicks. Model comparisons indicated that POT1 mRNA abundance was a largely better predictor of performance than telomere dynamics, indicating that telomere regulators may be powerful modulators of variation in life history strategies.

中文翻译：

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端粒调节基因POT1应对压力并预测自然行为：对端粒和生活史演变的影响

长的端粒几乎已经成为各种与健身有关的特征的代名词，并且可能是生活史策略中与生态有关的变异的中介。越来越多的证据表明，端粒动力学比长度本身更能预测性能，但是很少有工作考虑端粒调节机制如何应对环境挑战或影响自然界的性能。在这里，我们结合了来自自由活动的树燕（Tachycineta bicolor）的观察和实验数据集，以评估端粒调节基因POT1如何预测性能，端粒调节基因POT1编码一种在空间上阻止端粒酶修复端粒的庇护蛋白。首先，我们表明较低的POT1基因表达与较高的雌性质量（即较早繁殖）和较重的体重有关。接下来，我们用免疫应激源（注射脂多糖）挑战母亲，这会导致母亲患病并使其后代受到24小时食物限制。尽管POT1对母体注射无反应，但组成型基因表达较低的女性在治疗后能够更好地维持摄食率。母体注射也给雏鸡提供了一天的应激源，对它们的响应是POT1基因表达降低和端粒延长。其他假定的应激反应机制（即糖皮质激素，抗氧化剂）在对照组和应激雏鸡之间没有显着差异。模型比较表明，POT1 mRNA的丰度在很大程度上比端粒动力学更好地预测了性能，表明端粒调节剂可能是生命史策略变异的有力调节剂。