Transgenerational effects of parental age on fitness.

为什么生物会衰老？这是生物学中尚未解决的大问题之一，因为我们还不清楚一个最终降低适应性的过程是如何在进化中持续下去的，以及为什么物种没有进化得更长寿。已经提出了许多理论来从进化的角度解释为什么生物体会随着年龄的变化而变化，但很可能是许多因素导致了这种现象。然而，一个能强烈影响长寿选择压力的因素却没有得到太多的关注：衰老的跨代效应。表观遗传效应可以强烈影响某些进化模型的预测结果。影响健康的一个表观遗传和跨代因素是母亲的年龄。近世纪以来，人们都知道母亲的年龄会影响她后代的健康，甚至可能影响她孙子的健康。然而，所有相关研究都是在实验室中进行的。因此，这是未知的母亲年龄的影响是否在野生种群中运作，以及它是否可以有助于我们理解的长寿的进化。我们建议研究父母和祖父母的年龄对后代的寿命，繁殖成功率，生理和遗传学的影响在一个野生种群的家雀。我们从一项独特的、长期的家雀研究中获得了数据，可以详细研究这些主题。只有在像我们这样的封闭群体中，才有可能准确地估计寿命、健康和亲子关系，这些都是纵向研究父母年龄对个体健康的影响的先决条件。此外，我们将使用集中的实验与圈养鸟类巩固我们的假设，和基于个人的模拟模型，以探讨定量的影响，母亲的年龄对长寿的演变。我们预计，母亲的年龄对后代的健身表观遗传效应有重要影响的人口，反过来也对经典的权衡繁殖和生存。最终，这些效应将强烈影响作用于寿命本身的选择压力，并应导致长寿进化的新理论。

Why do organisms age? This is one of the big, unsolved questions in biology, because it is unclear how a process that ultimately decreases fitness can persist evolutionarily, and why species do not evolve to live longer. Many theories have been put forward to explain from an evolutionary perspective why organisms change with age, but it is likely that many factors contribute to the phenomenon. One factor that can strongly affect selection pressure for longevity has, however, not received much attention: the transgenerational effects of senescence. Epigenetic effects can strongly affect the predicted outcome of certain evolutionary models. One such epigenetic and trans-generational factor that affects fitness is maternal age. It has been known for nearly a century that a mother's age can affect her offspring's, and potentially even her grand-offspring's, fitness. However, all the relevant studies have been done in the laboratory. Therefore, it is unknown whether this effect of maternal age operates in wild populations, and whether it can contribute to our understanding of the evolution of longevity.We propose to study the effects of parental and grand-parental age on their offspring's lifespan, reproductive success, physiology and genetics in a wild population of house sparrows. We have data available from a uniquely suited, long-term study of house sparrows in which to examine these topics in detail. Only in a closed population such as the one that we have is it possible to accurately estimate lifespan, fitness and parentage, which are all prerequisites for the longitudinal study of parental age on individual fitness. In addition, we will use focused experiments with captive birds to cement our hypotheses, and individual-based simulation models to explore quantitatively the implications of maternal age effects on the evolution of longevity.We expect the epigenetic effects of maternal age on offspring fitness to have important consequences on the demography of a population, and in turn also on the balance of the classic trade-off between reproduction and survival. Ultimately, these effects will strongly affect the selection pressures acting on longevity itself, and should lead to novel theories of the evolution of longevity.