Predicting future generations

Now we can write the frequency of homozygotes in the next generation in terms of the frequency of homozygotes in the parental generation:

f' = 1/2N + 1-(1/2N)f

Since heterozygosity (H) = 1 - f , it can be shown to decrease at the following rate:

H' = 1 - (1/2N)H

This means that heterozygosity decreases at a rate of 1/(2N) per generation until it is zero. The population size, N , governs the influence of genetic drift: if N is small, the march to homozygosity is rapid, if it is infinitely large we have the Hardy-Weinberg equilibrium.