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A dynamical limit to evolutionary adaptation.
Melissa, Matthew J; Desai, Michael M.
Afiliación
  • Melissa MJ; Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138.
  • Desai MM; Department of Physics, Harvard University, Cambridge, MA 02138.
Proc Natl Acad Sci U S A ; 121(4): e2312845121, 2024 Jan 23.
Article en En | MEDLINE | ID: mdl-38241432
ABSTRACT
Natural selection makes evolutionary adaptation possible even if the overwhelming majority of new mutations are deleterious. However, in rapidly evolving populations where numerous linked mutations occur and segregate simultaneously, clonal interference and genetic hitchhiking can limit the efficiency of selection, allowing deleterious mutations to accumulate over time. This can in principle overwhelm the fitness increases provided by beneficial mutations, leading to an overall fitness decline. Here, we analyze the conditions under which evolution will tend to drive populations to higher versus lower fitness. Our analysis focuses on quantifying the boundary between these two regimes, as a function of parameters such as population size, mutation rates, and selection pressures. This boundary represents a state in which adaptation is precisely balanced by Muller's ratchet, and we show that it can be characterized by rapid molecular evolution without any net fitness change. Finally, we consider the implications of global fitness-mediated epistasis and find that under some circumstances, this can drive populations toward the boundary state, which can thus represent a long-term evolutionary attractor.
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Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Selección Genética / Tasa de Mutación Idioma: En Revista: Proc Natl Acad Sci U S A Año: 2024 Tipo del documento: Article

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Selección Genética / Tasa de Mutación Idioma: En Revista: Proc Natl Acad Sci U S A Año: 2024 Tipo del documento: Article