Agene has two al eles ëAí and ëaí with a frequency of p and q respectively the genotypic frequencies would
have the proportion :
(A) (p + q)²=1

(b) p²-q²-1

(c) pq = ½

(d) (p – q)²=1

The correct answer is (A) (p+q)²=1.

In the simplest case of a single locus with two alleles denoted A and a with frequencies f(A) = p and f(a) = q, respectively, the expected genotype frequencies are f(AA) = p² for the AA homozygotes, f(aa) = q² for the aa homozygotes, and f(Aa) = 2pq for the heterozygotes. The genotype proportions p², 2pq, and q² are called the Hardy-Weinberg proportions. Note that the sum of all genotype frequencies of this case is the binomial expansion of the square of the sum of p and q, and such a sum, as it represents the total of all possibilities, must be equal to 1.