Directional selection coupled with kin selection favors the establishment of senescence

BMC Biology

Research Article

Mauro Santos¹  András Szilágyi²  Tamás Czárán²  Eörs Szathmáry³ 

[1] Departament de Genètica i de Microbiologia, Grup de Genòmica, Bioinformàtica i Biologia Evolutiva (GBBE), Universitat Autònoma de Barcelona, Barcelona, Spain;cE3c – Centre for Ecology, Evolution and Environmental Changes & CHANGE – Global Change and Sustainability Institute, Lisbon, Portugal;Institute of Evolution, HUN-REN Centre for Ecological Research, Budapest, Hungary;Institute of Evolution, HUN-REN Centre for Ecological Research, Budapest, Hungary;Center for the Conceptual Foundations of Science, Parmenides Foundation, Pöcking, Germany;Department of Plant Systematics, Ecology and Theoretical Biology, Eötvös Loránd University, Budapest, Hungary;Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria;

关键词: Aging;    Evolution;    Longevity;    Evolvability;    Kin selection;   

DOI  :  10.1186/s12915-023-01716-w

 received in 2023-05-19, accepted in 2023-09-27,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundConventional wisdom in evolutionary theory considers aging as a non-selected byproduct of natural selection. Based on this, conviction aging was regarded as an inevitable phenomenon. It was also thought that in the wild organisms tend to die from diseases, predation and other accidents before they could reach the time when senescence takes its course. Evidence has accumulated, however, that aging is not inevitable and there are organisms that show negative aging even. Furthermore, old age does play a role in the deaths of many different organisms in the wild also. The hypothesis of programmed aging posits that a limited lifespan can evolve as an adaptation (i.e., positively selected for) in its own right, partly because it can enhance evolvability by eliminating “outdated” genotypes. A major shortcoming of this idea is that non-aging sexual individuals that fail to pay the demographic cost of aging would be able to steal good genes by recombination from aging ones.ResultsHere, we show by a spatially explicit, individual-based simulation model that aging can positively be selected for if a sufficient degree of kin selection complements directional selection. Under such conditions, senescence enhances evolvability because the rate of aging and the rate of recombination play complementary roles. The selected aging rate is highest at zero recombination (clonal reproduction). In our model, increasing extrinsic mortality favors evolved aging by making up free space, thereby decreasing competition and increasing drift, even when selection is stabilizing and the level of aging is set by mutation-selection balance. Importantly, higher extrinsic mortality is not a substitute for evolved aging under directional selection either. Reduction of relatedness decreases the evolved level of aging; chance relatedness favors non-aging genotypes. The applicability of our results depends on empirical values of directional and kin selection in the wild.ConclusionsWe found that aging can positively be selected for in a spatially explicit population model when sufficiently strong directional and kin selection prevail, even if reproduction is sexual. The view that there is a conceptual link between giving up clonal reproduction and evolving an aging genotype is supported by computational results.

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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