Evolution on genotype networks leads to phenotypic entrapment Articles uri icon

publication date

  • July 2013

start page

  • 1

end page

  • 5

international standard serial number (ISSN)

  • WWWW-0074

abstract

  • URL: arXiv:1307.0968v1 Nota: el título de la versión definitiva es Evolution on neutral networks accelerates the ticking rate of the molecular clock (se corresponde con AR/0000015335 ) -- Abstract: Large sets of genotypes give rise to the same phenotype because phenotypic expression is highly redundant. Accordingly, a population can accept mutations without altering its phenotype, as long as they transform its genotype into another one on the same set. By linking every pair of genotypes that are mutually accessible through mutation, genotypes organize themselves into genotype networks (GN). These networks are known to be heterogeneous and assortative. As these features condition the probability that mutations keep the phenotype unchanged---hence becoming blind to natural selection---it follows that the topology of the GN will influence the evolutionary dynamics of the population. In this letter we analyze this effect by studying the dynamics of random walks (RW) on assortative networks with arbitrary topology. We find that the probability that a RW leaves the network is smaller the longer the time spent in it---i.e., the process is not Markovian. From the biological viewpoint, this "phenotypic entrapment" entails an acceleration in the fixation of neutral mutations, thus implying a non-uniform increase in the ticking rate of the molecular clock with the age of branches in phylogenetic trees. We also show that this effect is stronger the larger the fitness of the current phenotype relative to that of neighboring phenotypes. -- DOI última versión (Evolution on neutral networks accelerates the ticking rate of the molecular clock): http://dx.doi.org/10.1098/rsif.2014.1010

keywords

  • populations and evolution; statistical mechanics; assortative networks; mutation accumulation