Disposable-soma senescence mediated by sexual selection in an ungulate
Disposable-soma senescence mediated by sexual selection in an ungulate
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DOI：
10.1038/nature03004
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发表时间：
2004-11-11
期刊：
影响因子：
64.8
通讯作者：
Mateos, C
中科院分区：
文献类型：
--
作者：
Carranza, J;Alarcos, S;Mateos, C
衰老可能是由于当前生殖投资和未来生殖所需的身体修复过程之间的最佳平衡（1），这是一个难以证明的理论预测，特别是在大型长寿动物中。在这里，我们建议，牙齿有固定的尺寸在生命的早期，但在咀嚼过程中磨损，可以采取的措施，总寿命的“修复”，和他们的磨损率作为衡量目前的支出在性能。我们的方法还考虑了性选择过程，以调查男性与女性相比衰老的进展，当选择有利于竞争配偶减少男性的生殖寿命时（2）。我们研究了2,141只不同年龄的雄性和739只雌性红鹿（马鹿）的尸体，发现雄性臼齿的大小远小于身体大小二型性的预期。这导致了更高的工作量，陡峭的磨损率和男性牙齿比女性更早耗尽，与性别特异性的终身表现和生殖模式一致。这些发现为衰老的可处置体细胞假说提供了实证支持（3），该假说预测，当由于其他限制生存或繁殖的原因而无法实现这种投资的回报时，对身体修复的投资将会减少。
Senescence may result from an optimal balance between current reproductive investment and bodily repair processes required for future reproduction(1), a theoretical prediction difficult to prove especially in large, long-lived animals. Here we propose that teeth that have fixed dimensions early in life, but that wear during chewing, can be taken as a measure of total lifetime 'repair', and their wear rate as a measure of current expenditure in performance. Our approach also considers the sexual selection process to investigate the advance of senescence in males compared with females, when selection favouring competition over mates reduces the reproductive lifespan of males(2). We studied carcasses of 2,141 male and 739 female red deer (Cervus elaphus) of different ages, finding that male molariform teeth emerged at a far smaller size than expected from body size dimorphism. This led to higher workload, steeper wear rate and earlier depletion of male teeth than in females, in concordance with sex-specific patterns of lifetime performance and reproduction. These findings provide the empirical support for the disposable-soma hypothesis of senescence(3), which predicts that investment in bodily repair will decrease when the return from this investment may not be realized as a result of other causes that limit survival or reproduction.