Cost-free lifespan extension via optimization of gene expression in adulthood aligns with the developmental theory of ageing

Lind, M. I., Carlsson, H., ML. Duxbury, E., Ivimey-Cook, E. and Maklakov, A. (2021) Cost-free lifespan extension via optimization of gene expression in adulthood aligns with the developmental theory of ageing. Proceedings of the Royal Society B: Biological Sciences, 288(1944), 20201728. (doi: 10.1098/rspb.2020.1728) (PMID:33529563) (PMCID:PMC7893226)

Abstract

Ageing evolves because the force of selection on traits declines with age but the proximate causes of ageing are incompletely understood. The ‘disposable soma’ theory of ageing (DST) upholds that competitive resource allocation between reproduction and somatic maintenance underpins the evolution of ageing and lifespan. In contrast, the developmental theory of ageing (DTA) suggests that organismal senescence is caused by suboptimal gene expression in adulthood. While the DST predicts the trade-off between reproduction and lifespan, the DTA predicts that age-specific optimization of gene expression can increase lifespan without reproduction costs. Here we investigated the consequences for lifespan, reproduction, egg size and individual fitness of early-life, adulthood and post-reproductive onset of RNAi knockdown of five ‘longevity’ genes involved in key biological processes in Caenorhabditis elegans. Downregulation of these genes in adulthood and/or during post-reproductive period increases lifespan, while we found limited evidence for a link between impaired reproduction and extended lifespan. Our findings demonstrate that suboptimal gene expression in adulthood often contributes to reduced lifespan directly rather than through competitive resource allocation between reproduction and somatic maintenance. Therefore, age-specific optimization of gene expression in evolutionarily conserved signalling pathways that regulate organismal life histories can increase lifespan without fitness costs.

• Item Type: Articles
• Keywords: Ageing, developmental theory of ageing, life-history evolution, lifespan, senescence.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ivimey-Cook, Dr Edward
• Authors: Lind, M. I., Carlsson, H., ML. Duxbury, E., Ivimey-Cook, E., and Maklakov, A.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Proceedings of the Royal Society B: Biological Sciences
• Publisher: Royal Society of London
• ISSN: 0962-8452
• ISSN (Online): 1471-2954
• Published Online: 03 February 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Proceedings of the Royal Society B: Biological Sciences 288(1944):20201728
• Publisher Policy: Reproduced under a Creative Commons licence