Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands.
School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia.
Mol Ecol. 2024 Aug;33(15):e17455. doi: 10.1111/mec.17455. Epub 2024 Jul 11.
Explaining variation in individual fitness is a key goal in evolutionary biology. Recently, telomeres, repeating DNA sequences capping chromosome ends, have gained attention as a biomarker for body state, physiological costs, and senescence. Existing research has provided mixed evidence for whether telomere length correlates with fitness, including survival and reproductive output. Moreover, few studies have examined how the rate of change in telomere length correlates with fitness in wild populations. Here, we intensively monitored an insular population of house sparrows, and collected longitudinal telomere and life history data (16 years, 1225 individuals). We tested whether telomere length and its rate of change predict fitness measures, namely survival, lifespan and annual and lifetime reproductive effort and success. Telomere length positively predicted short-term survival, independent of age, but did not predict lifespan, suggesting either a diminishing telomere length-survival correlation with age or other extrinsic factors of mortality. The positive association of telomere length with survival translated into reproductive benefits, as birds with longer telomeres produced more genetic recruits, hatchlings and reared more fledglings over their lifetime. In contrast, there was no association between telomere dynamics and annual reproductive output, suggesting telomere dynamics might not reflect the costs of reproduction in this population, potentially masked by variation in individual quality. The rate of change of telomere length did not correlate with neither lifespan nor lifetime reproductive success. Our results provide further evidence that telomere length correlates with fitness, and contribute to our understanding of the selection on, and evolution of, telomere dynamics.
解释个体适合度的变化是进化生物学的一个关键目标。最近，端粒，染色体末端重复的 DNA 序列，作为身体状态、生理成本和衰老的生物标志物引起了人们的关注。现有研究提供了关于端粒长度是否与适合度（包括生存和繁殖输出）相关的混合证据。此外，很少有研究检验野生种群中端粒长度变化率与适合度的关系。在这里，我们对一个岛屿麻雀种群进行了密集监测，并收集了纵向端粒和生活史数据（16 年，1225 只个体）。我们测试了端粒长度及其变化率是否可以预测适合度指标，即生存、寿命以及年度和终生繁殖努力和成功。端粒长度与短期生存呈正相关，与年龄无关，但与寿命无关，这表明随着年龄的增长，端粒长度与生存的相关性要么减弱，要么存在其他死亡的外在因素。端粒长度与生存的正相关关系转化为繁殖上的优势，因为端粒较长的鸟类在其一生中产生了更多的遗传后代、雏鸟和育雏。相比之下，端粒动态与年度繁殖输出之间没有关联，这表明在该种群中，端粒动态可能不会反映繁殖的成本，而可能被个体质量的变化所掩盖。端粒长度变化率与寿命或终生繁殖成功率均无相关性。我们的研究结果进一步证明了端粒长度与适合度相关，并有助于我们理解端粒动态的选择和进化。
