A benign juvenile environment reduces the strength of antagonistic pleiotropy and genetic variation in the rate of senescence.
A benign juvenile environment reduces the strength of antagonistic pleiotropy and genetic variation in the rate of senescence.
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DOI：
10.1111/1365-2656.12468
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发表时间：
2016-05
期刊：
影响因子：
--
通讯作者：
Velando A
中科院分区：
文献类型：
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作者：
Kim SY;Metcalfe NB;Velando A
环境在衰老的进化中可以发挥重要作用，因为体细胞维持和繁殖之间的最佳分配取决于影响预期寿命的外部因素。本研究的目的是通过实验测试生命早期的环境条件是否会影响衰老时间表，如果是的话，则要检查个体或基因型之间在衰老程度方面的差异是否因环境而异。我们通过对三刺刺鱼（Gasterosteus aculeatus，Linnaeus）进行实验，测试了生活史可塑性，并在反应规范框架内量化了不同环境中衰老模式的遗传影响，其中源自野生一年生种群的 F1 家族经历了不同的温度状况。与在更恶劣条件下发育的雄性刺鱼相比，在生命早期经历过更良性环境的雄性刺鱼随后在繁殖季节早期减少了对类胡萝卜素性信号的投入，因此在繁殖季节后期衰老速度较慢。这种衰老的可塑性是由基因决定的。拮抗性多效性和衰老速度的遗传变异仅在恶劣环境中长大的个体中才明显。影响生殖衰老率的基因型与环境相互作用的实验证明为环境在生命史进化中的作用提供了有趣的见解。结果表明，良性条件削弱了衰老进化的范围，并且对环境的依赖可能会在选择下维持遗传变异。
The environment can play an important role in the evolution of senescence because the optimal allocation between somatic maintenance and reproduction depends on external factors influencing life expectancy. The aims of this study were to experimentally test whether environmental conditions during early life can shape senescence schedules, and if so, to examine whether variation among individuals or genotypes with respect to the degree of ageing differs across environments. We tested life‐history plasticity and quantified genetic effects on the pattern of senescence across different environments within a reaction norm framework by using an experiment on the three‐spined stickleback (Gasterosteus aculeatus, Linnaeus) in which F1 families originating from a wild annual population experienced different temperature regimes. Male sticklebacks that had experienced a more benign environment earlier in life subsequently reduced their investment in carotenoid‐based sexual signals early in the breeding season, and consequently senesced at a slower rate later in the season, compared to those that had developed under harsher conditions. This plasticity of ageing was genetically determined. Both antagonistic pleiotropy and genetic variation in the rate of senescence were evident only in the individuals raised in the harsher environment. The experimental demonstration of genotype‐by‐environment interactions influencing the rate of reproductive senescence provides interesting insights into the role of the environment in the evolution of life histories. The results suggest that benign conditions weaken the scope for senescence to evolve and that the dependence on the environment may maintain genetic variation under selection.