Data from: Antagonistic pleiotropy and mutation accumulation contribute to age-related decline in stress response

As organisms age, the effectiveness of natural selection weakens, leading to age-related decline in fitness-related traits. The evolution of age-related changes associated with senescence is likely influenced by mutation accumulation (MA) and antagonistic pleiotropy (AP). MA predicts that age-related decline in fitness components is driven by age-specific sets of alleles, non-negative genetic correlations within trait across age, and an increase in the coefficient of genetic variance. AP predicts that age-related decline in a trait is driven by alleles with positive effects on fitness in young individuals and negative effects in old individuals, and is expected to lead to negative genetic correlations within traits across age. We build on these predictions using an association mapping approach to investigate the change in additive effects of SNPs across age and among traits for multiple stress-response fitness-related traits, including cold stress with and without acclimation and starvation resistance. We found support for both MA and AP theories of aging in the age-related decline in stress tolerance. Our study demonstrates that the evolution of age-related decline in stress tolerance is driven by a combination of alleles that have age-specific additive effects, consistent with MA, as well as non-independent and antagonistic genetic architectures characteristic of AP.

随着生物体衰老，自然选择的有效性逐步降低，进而引发与年龄相关的适合度相关性状衰退。与衰老相关的年龄变化的演化过程，大概率受到突变积累（mutation accumulation, MA）与拮抗多效性（antagonistic pleiotropy, AP）的影响。突变积累理论预测，适合度组分的年龄相关衰退由年龄特异性等位基因集合、跨年龄的同一性状内的非负遗传相关，以及遗传方差系数的升高共同驱动。拮抗多效性理论则预测，某一性状的年龄相关衰退由那些在年轻个体中对适合度具有正向效应、而在老年个体中具有负向效应的等位基因所驱动，且会引发跨年龄的同一性状内的负向遗传相关。本研究基于上述理论预测，采用关联作图（association mapping）方法，探究了单核苷酸多态性（single nucleotide polymorphism, SNPs）的加性效应在不同年龄以及不同性状间的变化，涵盖有无驯化条件下的冷胁迫与抗饥饿性。我们在胁迫耐受性的年龄相关衰退现象中，为衰老的突变积累与拮抗多效性两种理论均找到了支持证据。本研究表明，胁迫耐受性的年龄相关衰退演化，由兼具年龄特异性加性效应的等位基因（与突变积累理论相符），以及具备拮抗特性的非独立遗传结构（符合拮抗多效性理论的特征）共同驱动。