In a population of butterflies that has two alleles at a locus for spots, no spots (N) and spots (S), there are 20 individuals with the NN genotype, 40 with the NS genotype, and 40 with the SS genotype. What is the frequency of N in the population?
A) 0.4
B) 0.2
C) 0.6
D) 0.8
E) none of the above

Question

Quizplus · Accepted Answer

The frequency of N in the population can be calculated by taking the total number of N alleles and dividing it by the total number of alleles. There are 20 NN individuals (2N each), 40 NS individuals (1N each), and 40 SS individuals (0N). So, the total number of N alleles is (20*2) + (40*1) = 40 + 40 = 80. The total number of alleles is 2*(20+40+40) = 200. Therefore, the frequency of N is 80/200 = 0.4.

In a Population of Butterflies That Has Two Alleles at a Locus