Competition and fixation of cohorts of adaptive mutations under Fisher geometrical model.

Autor: Moura de Sousa JA; Instituto Gulbenkian de Ciência , Oeiras , Portugal., Alpedrinha J; Instituto Gulbenkian de Ciência , Oeiras , Portugal., Campos PR; Departamento de Fisica, Cidade Universitária, Universidade Federal de Pernambuco , Recife , Pernambuco , Brazil., Gordo I; Instituto Gulbenkian de Ciência , Oeiras , Portugal.
Jazyk: angličtina
Zdroj: PeerJ [PeerJ] 2016 Aug 02; Vol. 4, pp. e2256. Date of Electronic Publication: 2016 Aug 02 (Print Publication: 2016).
DOI: 10.7717/peerj.2256
Abstrakt: One of the simplest models of adaptation to a new environment is Fisher's Geometric Model (FGM), in which populations move on a multidimensional landscape defined by the traits under selection. The predictions of this model have been found to be consistent with current observations of patterns of fitness increase in experimentally evolved populations. Recent studies investigated the dynamics of allele frequency change along adaptation of microbes to simple laboratory conditions and unveiled a dramatic pattern of competition between cohorts of mutations, i.e., multiple mutations simultaneously segregating and ultimately reaching fixation. Here, using simulations, we study the dynamics of phenotypic and genetic change as asexual populations under clonal interference climb a Fisherian landscape, and ask about the conditions under which FGM can display the simultaneous increase and fixation of multiple mutations-mutation cohorts-along the adaptive walk. We find that FGM under clonal interference, and with varying levels of pleiotropy, can reproduce the experimentally observed competition between different cohorts of mutations, some of which have a high probability of fixation along the adaptive walk. Overall, our results show that the surprising dynamics of mutation cohorts recently observed during experimental adaptation of microbial populations can be expected under one of the oldest and simplest theoretical models of adaptation-FGM.
Databáze: MEDLINE