Filling a Gap in the Prediction of the Equilibrium Genetic Variance

We derive analytical predictions for the variance and kurtosis of the equilibrium distribution of allelic effects under stabilizing selection and drift, and for any value of the kurtosis of the distribution of the mutational effects. Numerical results relative to the equilibrium genetic variance are compared with other analytical predictions and with simulation results from the literature. Our prediction is superior for relatively weak selection (or relatively low variance of the mutational effects) and not to small population sizes, where previous methods overestimate the equilibrium genetic variance. The behavior of the equilibrium kurtosis is also illustrated.