Individuals in free-living animal populations generally differ substantially in reproductive success, lifespan and other fitness-related traits, but the molecular mechanisms underlying this variation are poorly understood. Telomere length and dynamics are candidate traits explaining this variation, as long telomeres predict a higher survival probability and telomere loss has been shown to reflect experienced "life stress." However, telomere dynamics among very long-lived species are unresolved. Additionally, it is generally not well understood how telomeres relate to reproductive success or sex. We measured telomere length and dynamics in erythrocytes to assess their relationship to age, sex and reproduction in Cory's shearwaters (Calonectris borealis), a long-lived seabird, in the context of a long-term study. Adult males had on average 231 bp longer telomeres than females, independent of age. In females, telomere length changed relatively little with age, whereas male telomere length declined significantly. Telomere shortening within males from one year to the next was three times higher than the interannual shortening rate based on cross-sectional data of males. Past long-term reproductive success was sex-specifically reflected in age-corrected telomere length: males with on average high fledgling production were characterized by shorter telomeres, whereas successful females had longer telomeres, and we discuss hypotheses that may explain this contrast. In conclusion, telomere length and dynamics in relation to age and reproduction are sex-dependent in Cory's shearwaters and these findings contribute to our understanding of what characterises individual variation in fitness.

中文翻译：

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特定性别的端粒长度和动态，与年龄和Cory剪水中的繁殖成功率有关。

自由生活动物种群中的个体在生殖成功，寿命和其他与健身有关的特征上通常存在很大差异，但对这种变异的分子机制了解甚少。端粒的长度和动力学是解释这种变化的候选特征，因为长的端粒预示着更高的生存概率，端粒的丢失已表明反映了经历的“生活压力”。然而，非常长寿的物种之间的端粒动力学尚未解决。另外，通常还不太了解端粒与生殖成功或性别的关系。在一项长期研究的背景下，我们测量了端粒的长度和红细胞的动力学，以评估它们与年龄，性别和繁殖力（长寿海鸟，Cory的剪枝水）之间的关系。成年男性平均端粒比女性长231 bp，与年龄无关。在女性中，端粒长度随年龄变化相对较小，而男性端粒长度则显着下降。根据男性的横断面数据，男性一年到下一年的端粒缩短比年间缩短率高三倍。过去的长期生殖成功在性别上反映在经年龄校正的端粒长度上：平均羽绒成熟度较高的雄性的端粒较短，而成功的雌性的端粒则较长，我们讨论了可以解释这种差异的假设。总之，在Cory'中端粒的长度和与年龄和生殖有关的动力学是性别依赖性的。