In addition, genes that are not associated with disease susceptibility when considered in isolation can be associated in the presence of a modifier allele of other gene.
During the gene conversion phase, each individual carrying the modifier allele of gene conversion was affected by gene conversion at rate rGC.
Further consider a modifier allele that on average has no main effect, but that increases variance in the trait (e.g. through epistatic interactions or by increasing mutation rate at the trait).
In addition, we simulated invasions of a modifier allele to a homogenous resident population at a mutation-selection balance.
We establish the conditions when a modifier allele can invade and when it becomes fixed if sufficiently frequent.
This threshold value is pivotal in determining whether the spread of a modifier allele causes the extinction of Wolbachia and was confirmed by simulation.
We ran two types of simulations: those with populations homogeneous at the modifier loci; and those of modifier allele invasions.
Further investigation of this variant as a low-penetrance modifier allele might be warranted.
Invasion was successful if the invading modifier allele took over the population significantly more often than expected for a neutral modifier (teh expected invasion success of a neutral allele is its initial frequency, 1% or 5%).
Then, an individual was chosen at random to carry the modifier allele, which allowed it to perform gene conversion.
