Neutral aggregation in finite-length genotype space

Authored by Bahram Houchmandzadeh

Date Published: 2017

DOI: 10.1103/physreve.95.012402

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

The advent of modern genome sequencing techniques allows for a more stringent test of the neutrality hypothesis of Darwinian evolution, where all individuals have the same fitness. Using the individual-based model of Wright and Fisher, we compute the amplitude of neutral aggregation in the genome space, i.e., the probability of finding two individuals at genetic (Hamming) distance k as a function of the genome size L, population size N nu and mutation probability per base nu. In well-mixed populations, we show that for N nu < 1/L, neutral aggregation is the dominant force and most individuals are found at short genetic distances from each other. For N nu >1, on the contrary, individuals are randomly dispersed in genome space. The results are extended to a geographically dispersed population, where the controlling parameter is shown to be a combination of mutation and migration probability. The theory we develop can be used to test the neutrality hypothesis in various ecological and evolutionary systems.
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models population Estimating evolutionary rates Substitutions Number