In a population of butterflies, blue wing color is determined by a dominant allele (B), green by a recessive allele (G). The frequency of B is 0.3. If the population is in H-W equilibrium, how many green winged butterflies do you expect in a population of 500?

a. 255

b. 245

c. 490

d. 0.70

e. 350

f. 150

b. 245

Explanation:

The Formula proposed by Hardy - Weinberg Equilibrium is:

p + q = 1

p² + 2pq + q² = 1

p is the frequency of the dominant allele.

q is the frequency of the recessive allele.

p² is the frequency of individuals with the homozygous dominant genotype.

2pq is the frequency of individuals with the heterozygous genotype.

q² is the frequency of individuals with the homozygous recessive genotype.

From the question, we were told that;

blue wing color is determined by a dominant allele (B) = p = 0.3

Then we are tasked with finding the frequency of recessive green allele (G). = q? (unknown)

From above equation; we have:

p + q = 1

Since p = 0.3, we can find q

q can now be;

q = 1 - p

q = 1 - 0.3

q = 0.7

If q = 0.7;

then q² = (0.7) ²

q² = 0.49

We can now multiply the frequency of individuals by the total population in order to get the number of individal with the given genotype were are tasked to find;

So, we have:

= 0.49 * 500

= 245

∴ From the total population; there are 245 green winged butterflies in population of 500 butterflies.