Are trade-offs really the key drivers of ageing and life span?
Are trade-offs really the key drivers of ageing and life span?
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DOI：
10.1111/1365-2435.13444
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发表时间：
2020-01-01
影响因子：
5.2
通讯作者：
Pavard, Samuel
中科院分区：
文献类型：
--
作者：
Cohen, Alan A.;Coste, Christophe F. D.;Pavard, Samuel
当前生命史理论和衰老生物学的思想表明，衰老率以及由此导致的寿命，在很大程度上是与繁殖相权衡的结果。虽然人们普遍认为存在各种进化限制，但它们在决定老龄化率方面的潜在作用却很少得到考虑。本综述整合了三种类型的信息，以评估制约因素和权衡因素在形成老龄化率方面的相对重要性：(a)关于种内权衡因素存在的实证工作；(b)关于限制权衡效力的因素的理论工作；(c)考虑目前所了解的衰老的生物学机制。在经验层面上，种内权衡的证据是混杂的，包括一些在模式生物中观察到权衡的令人惊讶的失败。在理论层面上，多种货币和非线性的存在会削弱权衡的强度和/或普遍性。此外，在较低级别职能之间进行权衡，例如在死亡率来源之间进行权衡，可能在较高的组织级别造成限制，例如，减少生育无法降低老龄化率。在衰老机制方面，一些机制，如IGF-1和相关途径的调节，似乎很好地同意权衡作为一种驱动力；然而，其他机制，如脊椎动物应激反应失调和干细胞衰竭，似乎更有可能施加限制，而不是调解权衡。综上所述，这些发现表明，仅靠权衡不足以理解老龄化速度是如何演变的；相反，权衡和约束可能在形成进化模式中发挥重要作用，它们的相对重要性在不同的分类群中有所不同。因此，现在是时候重新审视这个广泛的假设了，即生存与繁殖的权衡是构成生命史变异和老龄化速度进化的关键力量。在本文的支持信息中可以找到一个免费的简单语言摘要。
Current thinking in life-history theory and the biology of ageing suggests that ageing rates, and consequently life spans, evolve largely as a function of trade-offs with reproduction. While various evolutionary constraints are generally acknowledged to exist, their potential role in determining ageing rates is rarely considered. This review integrates three types of information to assess the relative importance of constraints and trade-offs in shaping ageing rates: (a) empirical work on the presence of intraspecific trade-offs; (b) theoretical work on factors limiting the force of trade-offs; and (c) consideration of the biological mechanisms of ageing, as currently understood. At the empirical level, evidence for intraspecific trade-offs is mixed, including some surprising failures to observe a trade-off in model organisms. At the theoretical level, the presence of multiple currencies and nonlinearity can weaken the strength and/or generality of trade-offs. Additionally, trade-offs among lower-level functions, such as between sources of mortality, can create constraints at higher organizational levels, for example such that reductions in reproduction are unable to produce decreases in ageing rate. In terms of ageing mechanisms, some mechanisms, such as the regulation of IGF-1 and related pathways, seem to agree quite well with trade-offs as a driving force; however, other mechanisms, such as dysregulation of the vertebrate stress response and stem cell exhaustion, seem more likely to impose constraints than to mediate trade-offs. Taken together, these findings suggest that trade-offs alone are insufficient to understand how ageing rates evolve; instead, both trade-offs and constraints likely play important roles in shaping evolutionary patterns, with their relative importance varying across taxa. Accordingly, it is time to revisit the broad assumption that survival-reproduction trade-offs are the key force structuring much of life-history variation and the evolution of ageing rates. A free Plain Language Summary can be found within the Supporting Information of this article.