Imagine a population with allele frequencies of 10 p and 90

Imagine a population with allele frequencies of 10% p and 90% q. In a population of 1000, how many individuals will express the p allele phenotype of p is a recessive allele? If it is a dominant allele?

Solution

10% p and 90% q p+q = 1 p = 10% = 0.1 q = 90% = 0.9 genotype frequency of AA (dominant) = p2 = 0.1 x 0.1 = 0.01 Frequency of Aa = 2 x 0.1 x 0.9 = 0.18 genotype frequency of aa (recessive) = q2 = 0.9 x 0.9 = 0.81 Thus p2 +2pq +q2 =1 0.01 + 0.18 + 0.81 =1 dominant phenotype is sum of p2 and 2pq = 0.18 + 0.01 = 0.19 recessive phenotype is q2 = 0.81 population of 1000 out of 1000, 190 individuals express p phenotype. p is showing recessive frequency. out of 1000, 810 individuals express q phenotype. q is showing dominant frequency.