Pathogen evolution within host individuals as a primary cause of senescence.
This paper discusses a novel theory of senescence: the community of pathogens within each host individual evolves during the life-time of the host, and in doing so progressively reduces host vigour. I marshal evidence that asymptomatic host individuals maintain persistent populations of viral pathogens; that these pathogens replicate; that they are often extremely variable; that selection within hosts causes the evolution of pathogens better able to exploit the host; that selection is host-specific; and that such evolving infections cause appreciable and progressive deterioration. Experimental approaches to testing the theory are discussed.
Bell
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Biology Department, McGill University, Montreal, Quebec, Canada.
D000375:Aging / Q000502:physiology*; D000818:Animals; D005075:Biological Evolution; D006678:HIV / Q000235:genetics; D006801:Humans; D008954:Models, Biological; D008957:Models, Genetic; D012641:Selection, Genetic; D014777:Virus Diseases / Q000382:microbiology*; D018406:Virus Physiological Phenomena; D014779:Virus Replication; D014780:Viruses / Q000235:genetics