Can someone explain how to solve this in detail? A population of water snakes is found...

Solution for question A:-

Island - Frequncy of banded snakes = 0.16 ie; genotype frequency of banded snakes (q²) = 0.16.

(given-banding is caused by recessive allele)

Therefore q = Squareroot of 0.16

q = 0.4

Mainland - Frequncy of banded snakes = 0.25 ie; genotype frequency of banded snakes (q²) = 0.25.

(given-banding is caused by recessive allele)

Therefore q = Squareroot of 0.25

q = 0.5

Thus frequency for alleles for bands on island and on mainland before migration is 0.4 and 0.5 respectively.

Solution for question B:-

Given Migration rate as 20% ie; 0.2

Now,

Change in recessive allele frequency (q_change)= migration rate * [recessive allele frequency of the migrants (Mainland) - recessive allele frequency of the host (island)]

Therefore q_change = 0.2 * (0.5 - 0.4)

q_change = 0.02.

Now,

Post migration frequency (recessive allele) at island q_new = pre migration frequency (recessive allele) at island + q_change

Therefore, q_new =0.4 + 0.02 = 0.42.

Post migration recessive allele frequency (banding allele) = 0.42