Effective population size for a sex-linked locus in populations under selection.

The problem of selection in the prediction of effective population size for a sex-linked locus was addressed in terms of the cumulative effect of selection on change in frequency of a sex-linked neutral gene. To express the cumulative effect of selection, a transition matrix approach was used. It was found that the terms accounting for the cumulative change in gene frequency show different expressions, depending on the gametic pathways. This dependency is due to the fact that the heterogametic sex transmits a sex-linked gene only to offspring of the homogametic sex, whereas the homogametic sex transmits to offspring of both sexes. Monte Carlo simulation was carried out to check the obtained prediction equation. The result showed that there is a good agreement between observed and predicted effective sizes.