Data from: Is telomere length a molecular marker of past thermal stress in wild fish?

Telomeres protect eukaryotic chromosomes; variation in telomere length has been linked (primarily in homoeothermic animals) to variation in stress, cellular ageing, and disease risk. Moreover, telomeres have been suggested to function as molecular markers for quantifying past environmental stress, but studies in wild animals remain rare. Environmental stress, such as extreme environmental temperatures in poikilothermic animals, may result in oxidative stress that accelerates telomere attrition. However, growth, which may depend on temperature, can also contribute to telomere attrition. To test for associations between multi-tissue telomere length and past water temperature while accounting for the previous individual growth, we used quantitative PCR to analyse samples from 112 young-of-the-year brown trout from 10 natural rivers with average water-temperature differences of up to 6°C (and an absolute maximum of 23 ºC). We found negative associations between relative telomere length (RTL) and both average river temperature and individual body size. We found no indication of RTL-temperature association differences among six tissues, but we did find indications for differences among the tissues for associations between RTL and body size; size trends, albeit non-significant in their differences, were strongest in muscle and weakest in fin. Although causal relationships among temperature, growth, oxidative stress, and cross-sectional telomere length remain largely unknown, our results indicate that telomere-length variation in a poikilothermic wild animal is associated with both past temperature and growth.

端粒（telomeres）可保护真核染色体；端粒长度的变异（主要在恒温动物中）已被证实与应激、细胞衰老及疾病风险的变异相关联。此外，端粒被提议作为量化过往环境应激的分子标志物，但针对野生动物的相关研究仍较为匮乏。环境应激，例如变温动物所遭遇的极端环境温度，可能引发氧化应激，进而加速端粒损耗。不过，可能依赖于温度的生长过程，同样会加剧端粒损耗。为了在考量个体既往生长情况的前提下，探究多组织端粒长度与过往水温之间的关联，我们采用定量PCR（quantitative PCR）技术，分析了源自10条天然河流的112尾当年生褐鳟样本，这些河流的平均水温差异最高可达6℃，绝对温差最大值为23℃。我们发现相对端粒长度（RTL）与河流平均水温及个体体长均呈负相关关联。未观察到六种组织间的RTL-水温关联存在差异，但却发现不同组织在RTL与体长的关联上存在差异；尽管该差异未达到统计学显著性，但体长相关趋势在肌肉组织中最为显著，鳍组织中则最弱。尽管温度、生长、氧化应激与横断面端粒长度之间的因果关系仍尚未完全明晰，但我们的研究结果表明，变温野生动物的端粒长度变异与过往水温及个体生长均存在关联。