Effects of gene expression noise on phenotype and cooperate-defect fitness

The models of evolutionary dynamics are usually based in a fixed background fitness, and when they include cooperation, they also include a fixed degree of cooperation. However, in a biological system each individual is going to have different fitness and cooperate in different degrees due to phenotypic variability, even in isogenic populations. This is an effect of the gene expression noise. Expression noise affects the fitness of an organism when its fitness depends on the advantage of some phenotype that is generated by a gene or group of genes, and an increase in gene noise expression can lead to a decrement of the average total fitness of organisms. We first set up an stochastic program for individual and group selection with fixed background fitness and cooperation level. The results of these stochastic simulations were corroborated and compared to the analytical stochastic model and some approximations for large populations and weak selection. Then we introduced phenotype variability in the case of individual selection and finally we adapted the simulation to a common goods game for group selection with cooperation variability. Our stochastic simulations show that the fixation times are altered if the background fitness is a non-linear function of the gene expression level, as so changes in fixation probability with the variance of the fitness distribution. Including phenotypic variability in Moran processes allows a more realistic approach to the process of individual selection (Natural Selection), and the evolution of cooperation and group selection(Natural selection at a second level). Detailed simulations of competition populations of cooperators and defectors would allow characterization of the importance of phenotypic variability and its utility or impact in an evolutionary process.

• Autores: Mahecha González, Luis Alejandro
• Fecha de publicación: 2012
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/12168
• Acceso en línea: http://hdl.handle.net/1992/12168
• Palabra clave: Expresión génica - Investigaciones; Fenotipos - Investigaciones; Aptitudes físicas - Investigaciones; Física
• Rights: openAccess
• License: http://creativecommons.org/licenses/by-nc-sa/4.0/