Example:M and N are different blood antigens specified by alleles of the same gene.The antigens are codominant so a simple blood test can distinguish the three possible genotypes. fM/M)=0.83,fM/n)=0.16,fNN)=.01 p=f(M)=.83+.08=0.91 q=fN)=.01+.08=0.09 Note:we can get both p and q with just two of the genotype frequencies because the three genotype frequencies must total to a frequency of 1.0: f(M/M)+f(M/N)f(N/N)=1 Now let's think about how the inverse calculation would be performed.That is,how to derive the genotype frequencies from the allele frequencies.To do this we must make an assumption about the frequency of mating of individuals with different genotypes.If we assume that the gametes mix at random,we can calculate the compound probabilities of obtaining each possible combination of alleles. egg A 9 sperm (p) (q) A AIA Ala p2) (pq) q Ala ala (q) (pq) g2) Thus the genotype frequencies for the next generation are: f(A/A)=p2.f(A/a)2pg,f(ala)g2Example: M and N are different blood antigens specified by alleles of the same gene. The antigens are codominant so a simple blood test can distinguish the three possible genotypes. f(M/M) = 0.83, f(M/n) = 0.16, f(N/N) = .01 p = f(M) = .83 + .08 = 0.91 q = f(N) = .01 + .08 = 0.09 Note: we can get both p and q with just two of the genotype frequencies because the three genotype frequencies must total to a frequency of 1.0: f(M/M) + f(M/N) + f(N/N) = 1 Now let's think about how the inverse calculation would be performed. That is, how to derive the genotype frequencies from the allele frequencies. To do this we must make an assumption about the frequency of mating of individuals with different genotypes. If we assume that the gametes mix at random, we can calculate the compound probabilities of obtaining each possible combination of alleles. egg A a sperm (p) (q) A (p) A/A (p2) A/a (pq) a (q) A/a (pq) a/a (q2) Thus the genotype frequencies for the next generation are: f(A/A) = p2, f(A/a) = 2pq, f(a/a) = q2