It would seem to me that after monohybrid mating, the frequency of the dominant and recessive allele should change? I will donate original frequency (i.e. proportion) by f_{0} and that after mating by f_{1}. f_{1}(Dom-Dom) = f_{0}(Dom-Dom)^{2} + 1/2 * f_{0}(Dom-Dom) * f_{0}(Dom-Rec) + 1/4 * f_{0}(Dom-Rec)^{2} Am I right so far? (I hope my notation is intelligible - f_{0}(Genotype) is the fraction of the genotype, in the original population.) Then we can replace the terms to find f_{1}(Dom-Dom) = P(Dom)^{4} + 1/2 * P(Dom)^{2} * 2*P(Dom)*(1-P(Dom)) + 1/4 * (2*P(Dom)*(1-P(Dom)))^{2} = P(Dom)^{4} - P(Dom)^{3} + P(Dom)^{2}. Where P(Dom) is the frequency of the dominant allele and P(Rec) is the frequency of the recessive allele, P(Dom)+P(Rec)=1, in the original population. Thus it would seem that the frequency of the allele has changed due to the mating?
You forgot a factor of 2 in the fraction of Dom-Dom/Dom-rec matings to account for the combinatorics [i.e. the probability of a homozygous dominant individual mating with a heterozygote is 2*f(Dom-Dom)*f(Dom-rec)].
Ah I see. And any mating between two individuals with different genotypes would also have this multiplying factor of 2 in the calculation of its probability?