Question

Within a population of butterflies, wing color can be brown or yellow. One gene with two alleles, dominant brown (B) or recessive yellow (b). In this population, 40% (0.40) of all butterflies are yellow. Given this information, determine the allele frequencies for both the B and b alleles. Show all of your calculations clearly.

Answer 1

Given information:

WING COLOR- brown (dominant)-B_

- yellow (recessive)- bb

40% of all butterflies are yellow

Hence, 40/100 or 0.4 butterflies have genotype bb

According to Hardy Weinberg Law,

p + q = 1 (or p^2+ q^2+ 2pq= 1)

Where p= frequency of dominant allele (B)

And q= frequency of recessive allele (b)

Given = q^2 (q square) = 40% or 0.4

So, q= √0.4

=0.63

Applying the Hardy Weinberg equation

p+ q = 1 we can calculate p

So p+ 0.63 = 1

p = 1-0.63

= 0.37

Hence, frequency of allele B is 0.37 or 37%

And frequency of allele b is 0.4 or 40% in the population.

Hope this helps.

:)