Data from: Experimental evolution of slowed cognitive aging in Drosophila melanogaster

Reproductive output and cognitive performance decline in parallel during aging, but it is unknown whether this reflects a shared genetic architecture or merely the declining force of natural selection acting independently on both traits. We used experimental evolution in Drosophila melanogaster to test for the presence of genetic variation for slowed cognitive aging, and assess its independence from that responsible for other traits’ decline with age. Replicate experimental populations experienced either joint selection on learning and reproduction at old age (Old+Learning), selection on late-life reproduction alone (Old), or a standard two-week culture regime (Young). Within 20 generations, the Old+Learning populations evolved a slower decline in learning with age than both the Old and Young populations, revealing genetic variation for cognitive aging. We found little evidence for a genetic correlation between cognitive and demographic aging: although the Old+Learning populations tended to show higher late-life fecundity than Old populations, they did not live longer. Likewise, selection for late reproduction alone did not result in improved late-life learning. Our results demonstrate that Drosophila harbor genetic variation for cognitive aging that is largely independent from genetic variation for demographic aging and suggest that these two aspects of aging may not necessarily follow the same trajectories.

衰老过程中，繁殖产出与认知能力会同步衰退，但目前尚不明确这种同步衰退究竟源于二者共享的遗传架构，还是仅由分别作用于这两种性状的自然选择作用强度随衰老进程逐渐减弱所导致。本研究利用黑腹果蝇（Drosophila melanogaster）的实验进化体系，检测是否存在可延缓认知衰老的遗传变异，并评估该变异与调控其他衰老相关性状衰退的遗传变异是否相互独立。我们将重复实验种群分为三组：分别接受老年阶段学习能力与繁殖能力的联合选择（Old+Learning组）、仅接受老年阶段繁殖能力选择（Old组），以及采用标准两周培养体系的对照组（Young组）。经过20代实验进化后，Old+Learning组的学习能力随年龄衰退的速度显著慢于Old组与Young组，这表明果蝇种群中存在调控认知衰老的遗传变异。本研究未发现认知衰老与生命史衰老之间存在显著遗传相关的证据：尽管Old+Learning组的晚年繁殖力普遍高于Old组，但二者的寿命并无显著差异。同样，仅针对晚年繁殖能力的选择，并未使果蝇的晚年学习能力得到提升。本研究结果证实，黑腹果蝇中存在调控认知衰老的遗传变异，且该变异与调控生命史衰老的遗传变异基本相互独立；这表明衰老的两个维度未必会遵循相同的衰退轨迹。