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）可保护真核生物染色体；其长度变异已被证实与应激、细胞衰老及疾病风险的变异相关，该关联主要在恒温动物（homoeothermic animals）中得到确认。此外，端粒还被提议作为量化过往环境应激的分子标记（molecular markers），但针对野生动物的相关研究仍较为匮乏。诸如变温动物（poikilothermic animals）遭遇的极端环境温度这类环境应激，可能引发氧化应激（oxidative stress），进而加速端粒损耗。而生长过程——其可能受温度调控——同样会加剧端粒损耗。为探究多组织端粒长度与过往水温之间的关联，并控制个体既往生长状况的影响，我们采用定量PCR（quantitative PCR）技术，对源自10条天然河流的112尾当年生褐鳟样本进行了分析；这些河流的平均水温差异最高可达6℃，绝对最高水温为23℃。研究结果显示，相对端粒长度（relative telomere length，RTL）与河流平均水温及个体体长均呈负相关关系。未观察到6种组织中RTL与水温的关联存在显著差异，但确实发现不同组织中RTL与体长的关联存在差异；尽管组间差异未达统计学显著性，但体长相关的趋势在肌肉组织中最为显著，在鳍组织中最弱。尽管温度、生长、氧化应激与横断面端粒长度之间的因果关联目前仍大多未明，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生长情况均存在关联。