You are studying a population of sunflowers and you observe

You are studying a population of sunflowers and you observe that there are two alleles for stem length. Allele 1 codes for fat stems and is dominant over allele 2, which codes for thin stems. Allele 2 is at a frequency of 20% of the population, what should be the frequency of allele 1 homozygotes?

A.0.04

Solution

According to Hardy-Weinberg Law, if the allele freuqencies of two alleles in a population is represented by p and q, then the below given mathematical equations hold true:

p² + q² +2pq = 1

and p+q= 1

According to the information, the genetic frequency of allele is 20%. This suggests that every 20 individuals out of 100 will have this allele.

Thus the allele frequency will be given by p² or (20*20)/(100*100) or 0.04.

Thus, choice A is correct answer.