Question

Consider a population of frogs. Allele B1 codes for spotted frogs; allele B2 codes for non-spotted frogs. B1 is dominant to B2 .

The allele frequencies on the mainland are B1 = 0.75 and B2 = 0.25.

The allele frequencies on the island are B1 = 0.55 and B2 = 0.45. There are 170 frogs on the island.


During a storm, 30 non-spotted frogs come to the island by floating on debris. What are the new frequencies of B1 and B2 on the island?

Enter your answer as two numbers (each to two decimal places), separated by a comma. (Example: 0.56, 0.44)

Answer 1

Frequency of B1 = 0.47

Frequency of B2 = 0.53

Hope this helps!

Answer 2

Answer: (p,q) = (0.27,0.73)

Step-by-step explanation: In the island, the frequency of B1, which is dominant is: p=0.55 and for B2 is q=0.45. In total, there are 170 frogs.

Individuals with B2 allele in the island:

170*0.45 = 76.5

During the storm, 30 frogs with recessive characteristics went to the island, which means that the population of frogs which has recessive genotype increased, so did its frequency and general population:

New total of frogs: 170 + 30 = 200

New frequency of B2 frogs:

76.5 + 30 = 106.5

`q^(2) =(106.5)/(200)`

`q = √(0.5325)`

q = 0.73

With the frequency of recessive and as p + q = 1,

p = 1 - q

p = 1 - 0.73

p = 0.27

Thus, the new frequencies for B1 and B2 in the island is (0.27,0.73) respectively.