arXiv subjects

Nigel Snoad

Publications and source records attributed to Nigel Snoad.

3 recordsLinked to original sources

arXiv2000

Quasispecies evolution on a fitness landscape with a fluctuating peak

A quasispecies evolving on a fitness landscape with a single peak of fluctuating height is studied. In the approximation that back mutations can be ignored, the rate equations can be solved analytically. It is shown that the error threshold on this class of dynamic landscapes is defined by the time average of the selection pressure. In the case of a periodically fluctuating fitness peak we also study the phase-shift and response amplitude of the previously documented low-pass filter effect. The special case of a small harmonic fluctuation is treated analytically.

physics.bio-ph↗

arXiv2000

Optimal Mutation Rates in Dynamic Environments

In this paper we study the evolution of the mutation rate for simple organisms in dynamic environments. A model with multiple fitness coding loci tracking a moving fitness peak is developed and an analytical expression for the optimal mutation rate is derived. Surprisingly it turns out that the optimal mutation rate per genome is approximately independent of genome length, something that also has been observed in nature. Simulations confirm the theoretical predictions. We also suggest an explanation for the difference in mutation frequency between RNA and DNA based organisms.

physics.bio-ph↗

arXiv1999

Error Thresholds on Dynamic Fittness-Landscapes

In this paper we investigate error-thresholds on dynamics fitness-landscapes. We show that there exists both lower and an upper threshold, representing limits to the copying fidelity of simple replicators. The lower bound can be expressed as a correction term to the error-threshold present on a static landscape. The upper error-threshold is a new limit that only exists on dynamic fitness-landscapes. We also show that for long genomes on highly dynamic fitness-landscapes there exists a lower bound on the selection pressure needed to enable effective selection of genomes with superior fitness independent of mutation rates, i.e., there are distinct limits to the evolutionary parameters in dynamic environments.

physics.bio-ph↗