Rose Michael R, Rauser Casandra L, Mueller Laurence D, Benford Gregory
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697-2525, USA.
Biogerontology. 2006 Aug;7(4):269-77. doi: 10.1007/s10522-006-9001-6. Epub 2006 Apr 13.
In the year 1992, two publications on age-specific mortality rates revealed a cessation of demographic aging at later ages in very large cohorts of two dipteran species reared under a variety of conditions. Despite some initial concerns about possible artifacts, these findings have now been amply corroborated in the experimental literature. The eventual cessation of aging undermines the credibility of simple Gompertzian aging models based on a protracted acceleration in age-specific mortality during adulthood. The first attempt to explain the apparent cessation of aging was extreme lifelong heterogeneity among groups with respect to frailty. This lifelong heterogeneity theory assumes an underlying Gompertzian aging affecting every member of an adult cohort, with a merely apparent cessation of aging explained in terms of the increasing domination of a slowly aging group among the survivors to late ages. This theory has received several experimental refutations. The second attempt to explain the cessation of aging applied force of natural selection theory. This explanation of the cessation of aging has been corroborated in several Drosophila experiments. In particular, this theory requires that both age-specific survival and age-specific fecundity cease declining in late life, which has now been experimentally established. This theory also predicts that the timing of the cessation of aging should depend on the last age of reproduction in a population's evolutionary history, a prediction that has been corroborated. While lifelong heterogeneity should reduce average age-specific mortality in late life whenever it is pronounced, the cessation of aging in late life can be explained by plateaus in the forces of natural selection whether lifelong heterogeneity is present or not. The discovery that aging ceases is one of the most significant discoveries in recent aging research, with potentially revolutionary scientific implications.
1992年，两篇关于特定年龄死亡率的论文表明，在各种条件下饲养的两个双翅目物种的非常大的群体中，晚年的人口老龄化停止了。尽管最初有人担心可能存在人为因素，但这些发现现在已在实验文献中得到充分证实。衰老的最终停止削弱了基于成年期特定年龄死亡率长期加速的简单冈珀茨衰老模型的可信度。解释衰老明显停止的首次尝试是群体之间在脆弱性方面存在极端的终身异质性。这种终身异质性理论假设潜在的冈珀茨衰老影响成年群体的每个成员，只是衰老的明显停止是根据幸存者中缓慢衰老群体在晚年的主导地位增加来解释的。这一理论已遭到多次实验反驳。解释衰老停止的第二次尝试应用了自然选择理论的力量。衰老停止的这种解释已在多个果蝇实验中得到证实。特别是，这一理论要求特定年龄的生存率和特定年龄的繁殖力在晚年都停止下降，这一点现在已通过实验得到证实。该理论还预测，衰老停止的时间应该取决于一个种群进化历史中的最后繁殖年龄，这一预测已得到证实。虽然终身异质性在显著时应会降低晚年的平均特定年龄死亡率，但无论是否存在终身异质性，晚年衰老的停止都可以用自然选择力量的平稳期来解释。衰老停止的发现是最近衰老研究中最重要的发现之一，具有潜在的革命性科学意义。
