Data from: Intergenerational effects on offspring telomere length; interactions among maternal age, stress exposure and offspring sex

Offspring produced by older parents often have reduced longevity, termed the Lansing Effect. Because adults usually have similar aged-mates, it is difficult to separate effects of maternal and paternal age, and environmental circumstances are also likely to influence offspring outcomes. The mechanisms underlying the Lansing Effect are poorly understood. Variation in telomere length and loss, particularly in early life, is linked to longevity in many vertebrates and therefore changes in offspring telomere dynamics could be very important in this context. We examined the effect of maternal age and environment on offspring telomere length in zebra finches. We kept mothers under either control (ad lib food) or more challenging (unpredictable food) circumstances and experimentally minimised paternal age and mate choice effects. Irrespective of the maternal environment, there was a substantial negative effect of maternal age on offspring telomere length, evident in longitudinal and cross sectional comparisons (average of 39% shorter). Furthermore, in young mothers, sons reared by challenged mothers had significantly shorter telomere lengths than sons reared by control mothers. This effect disappeared when the mothers were old, and was absent in daughters. These findings highlight the importance of telomere dynamics as inter-generational mediators of the evolutionary processes determining optimal age-specific reproductive effort and sex allocation.

父母年龄较大时所产生的后代往往寿命缩短，该现象被称为兰辛效应（Lansing Effect）。由于成年个体通常拥有年龄相近的配偶，因此难以区分母体与父体年龄的独立影响，且环境因素同样可能影响后代的发育结局。目前学界对兰辛效应背后的潜在机制仍知之甚少。端粒（telomere）长度与损耗的变化，尤其是生命早期的相关变化，与众多脊椎动物的寿命密切相关，因此后代端粒动力学的改变在此类研究中或发挥关键作用。我们以斑胸草雀（zebra finches）为实验对象，探究了母体年龄与环境对后代端粒长度的影响。实验中，我们将母体分为两组：对照组（自由采食）与挑战性环境组（食物供给不可预测），并通过实验手段尽可能控制父体年龄与配偶选择带来的干扰。无论母体所处环境如何，母体年龄对后代端粒长度均存在显著负向影响：纵向与横断面研究对比均显示，后代端粒长度平均缩短39%。此外，在年轻母体所育后代中，挑战性环境组母体所育雄性后代的端粒长度显著短于对照组母体所育雄性后代；而当母体年龄较大时，该效应消失，且在雌性后代中未观察到此现象。本研究结果凸显了端粒动力学作为跨代介导因子的重要性，其可调控决定特定年龄阶段最优繁殖投入与性别分配的进化过程。