Telomere length and dynamics predict mortality in a wild longitudinal study

Explaining variation in life expectancy between individuals of the same age is fundamental to our understanding of population ecology and life-history evolution. Variation in the length and rate of loss of the protective telomere chromosome caps has been linked to cellular lifespan. Yet, the extent to which telomere length and dynamics predict organismal lifespan in nature is still contentious. Using longitudinal samples taken from a closed population of Acrocephalus sechellensis (Seychelles warblers) studied for over 20 years, we describe the first study into life-long adult telomere dynamics (1 to 17 years) and their relationship to mortality in natural conditions (N=204 individuals). We show that telomeres shorten with increasing age and body mass, and that shorter telomeres and greater rates of telomere shortening predicted future mortality. Our results provide the first clear and unambiguous evidence of a relationship between telomere length and mortality in the wild, and substantiate the prediction that telomere length and shortening rate can act as an indicators of biological age further to chronological age when exploring life-history questions in natural conditions.阐释同年龄段个体间预期寿命的差异，是我们理解种群生态学（population ecology）与生活史进化（life-history evolution）的核心基础。端粒（telomere）长度及其缩短速率的变异，已被证实与细胞寿命存在关联。然而，在自然环境中端粒长度与动态变化对生物体寿命的预测能力究竟可达何种程度，目前仍存在争议。我们采用了取自一个被持续研究超20年的塞舌尔苇莺（Acrocephalus sechellensis）封闭种群（closed population）的纵向样本（longitudinal sample），开展了此项研究：这是首个针对成年个体终生端粒动态变化（1至17年）及其在自然条件下与死亡率（mortality）关联的研究，共纳入204个个体。本研究证实，端粒会随年龄增长与体重增加而缩短，且更短的端粒与更快的端粒缩短速率可预测个体未来的死亡风险。本研究的结果首次为野生种群中端粒长度与死亡率之间的关联提供了清晰且无歧义的证据，并证实了这一预测：在自然环境中开展生活史相关研究时，端粒长度与缩短速率可作为比时序年龄（chronological age）更具参考价值的生物学年龄（biological age）指标。