Answer:
b. 2pq
Explanation:
If there exist a population of 100 individuals and we have a cross between two heterozygous individuals
i.e Aa × Aa
A a
A AA Aa
a Aa aa
we can see that the proportion of the offspring are:
AA = 1/4 which is equivalent to 25 %
Aa = 2/4 which is equivalent to 50 %
aa = 1/4 which is equivalent to 25 %
Now, in solving Hardy Weinberg Equilibrium
There are two equation involved.
p + q = 1
p² + 2pq + q² = 1
where:
p² exist as the frequency of individual with homozygous dominant genotype(AA) = 25%
2pq as the frequency of individual with the heterozygous genotype (Aa) = 50%
q² exist as the frequency of individual with homozygous recessive genotype(aa) = 25%
As such, the frequency of the heterozygous Aa genotype to the appropriate part of the Hardy-Weinberg equilibrium equation is 2pq.