Data from: Repeated intraspecific divergence in life span and aging of African annual fishes along an aridity gradient

Life span and aging are substantially modified by natural selection.
Across species, higher extrinsic (environmentally related) mortality (and
hence shorter life expectancy) selects for the evolution of more rapid
aging. However, among populations within species, high extrinsic mortality
can lead to extended life span and slower aging as a consequence of
condition-dependent survival. Using within-species contrasts of eight
natural populations of Nothobranchius fishes in common garden experiments,
we demonstrate that populations originating from dry regions (with short
life expectancy) had shorter intrinsic life spans and a greater increase
in mortality with age, more pronounced cellular and physiological
deterioration (oxidative damage, tumor load), and a faster decline in
fertility than populations from wetter regions. This parallel
intraspecific divergence in life span and aging was not associated with
divergence in early life history (rapid growth, maturation) or
pace-of-life syndrome (high metabolic rates, active behavior). Variability
across four study species suggests that a combination of different aging
and life-history traits conformed with or contradicted the predictions for
each species. These findings demonstrate that variation in life span and
functional decline among natural populations are linked, genetically
underpinned, and can evolve relatively rapidly.

寿命与衰老过程在极大程度上受自然选择的调控。跨物种层面，更高的外在（环境相关）死亡率（由此预期寿命更短）会推动演化出更快的衰老速率。然而在同一物种的不同种群之间，高外在死亡率却可能因条件依赖型存活的缘故，导致更长的寿命与更缓慢的衰老。本研究通过对8个自然种群的假鳃鳉属（Nothobranchius）鱼类开展同质园实验的种内对比分析，结果显示：相较于湿润区域来源的种群，源自干旱区域（预期寿命更短）的种群拥有更短的固有寿命，随年龄增长的死亡率增幅更高，细胞与生理退化（氧化损伤、肿瘤负荷）更为显著，且生育力下降速率更快。这种寿命与衰老层面的平行种内分化，并未与早期生活史（快速生长、成熟）或生活节奏综合征（高代谢率、活跃行为）的分化产生关联。对4个研究物种的分析显示，不同衰老与生活史特征的组合，在各物种中分别符合或违背了相关预测。本研究结果表明，自然种群间的寿命与功能衰退差异存在遗传基础且彼此关联，且能够相对快速地发生演化。