Imagine a population with a gene that has 2 alleles: A1 (dominant) & A2 (recessi
ID: 177037 • Letter: I
Question
Imagine a population with a gene that has 2 alleles: A1 (dominant) & A2 (recessive). Each allele occurs in
the population with a frequency of about 50%. Assuming all else is equal, what will be the eventual equilibrium
frequency of the two alleles?
a. A1 will become fixed (frequency 100%).
b. A1 will increase to a frequency of 75%.
c. A2 will become fixed (frequency of 100%).
d. Evolution will occur, but the outcome is unpredictable.
e. Nothing will change (frequencies will remain about 50%).
Explanation / Answer
Answer:
e. Nothing will change (frequencies will remain about 50%).
A1 frequency = 50/500 = 0.5
A2 frequency = 0.5
A1A1 frequency = p^2 =0.5 * 0.5 = 0.25
A2A2 frequency = q^2 0.5 * 0.5 = 0.25
A1A2 frequency =2pq = 2 * 0.5 * 0.5 = 0.5
p^2 + 2pq + q^2 = 1
0.25 + 0.5 + 0.25= 1