Some Consequences of Demographic Stochasticity in Population Genetics

Parsons, T. L., Quince, C. and Plotkin, J. B. (2010) Some Consequences of Demographic Stochasticity in Population Genetics. Genetics, 185(4), pp. 1345-1354. (doi: 10.1534/genetics.110.115030)

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Publisher's URL: http://dx.doi.org/10.1534/genetics.110.115030

Abstract

Much of population genetics is based on the diffusion limit of the Wright-Fisher model, which assumes a fixed population size. This assumption is violated in most natural populations, particularly for microbes. Here we study a more realistic model that decouples birth and death events and allows for a stochastically varying population size. Under this model, classical quantities such as the probability of and time before fixation of a mutant allele can differ dramatically from their Wright-Fisher expectations. Moreover, inferences about natural selection based on Wright-Fisher assumptions can yield erroneous and even contradictory conclusions: at small population densities one allele will appear superior, whereas at large densities the other allele will dominate. Consequently, competition assays in laboratory conditions may not reflect the outcome of long-term evolution in the field. These results highlight the importance of incorporating demographic stochasticity into basic models of population genetics.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Quince, Dr Christopher
Authors: Parsons, T. L., Quince, C., and Plotkin, J. B.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Genetics
ISSN:0016-6731

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
503351Pioneering the genomics era of environmental microbiologyChristopher QuinceEngineering & Physical Sciences Research Council (EPSRC)EP/H003851/1Infrastructure and Environment