I was looking at some Olympiad questions and came across the following:
If the frequency of a completely recessive allele is $0.2$ and it remains unchanged from generation to generation due to superior fitness of heterozygotes, then find the intensity of selection against the dominant homozygotes.
As far as I know, selection intensity is a quantitative measure of the superiority of the individuals selected for breeding. However, I am not really aware of how to compute its numerical value.
The best I could do was to assume that the frequency would be a ratio of the selection coefficient of recessive homozygotes ($s$) to that of the sum of selection coefficients of both recessive ($s$)and dominant homozygotes ($t$), i.e. $\frac{s}{s+t}$, but that doesn't seem to lead me anywhere. Also, I can't think of a concrete reason as to why the frequency would be of this form if it is actually.
Any suggestions/pointers would be much appreciated.
