Answer:
If D is dominant and d is recessive, 160 with DD, 360 with Dd, and 480 with dd
Explanation:
if p= the frequency of the dominant allele (D for dark hair, perhaps?)
and q= the frequency of the recessive allele (d for not dark hair?)
remember that p + q = 1
400/1000= frequency of D= 0.4
0.4 + q = 1
q= 0.6 = frequency of d
remember also that p^2 +2pq + q^2 = 1
p^2 = (0.4)(0.4)= 0.16 = DD
q^2 = (0.6)(0.6) = 0.36 = Dd
2pq= (2)(0.4)(0.6)= 0.48 = dd
We now have the frequencies of each genotype and can apply them to the population size.
(0.16)(1000 mice) = 160 mice with DD
(0.36)(1000 mice) = 360 mice with Dd
(0.48)(1000 mice) = 480 mice with dd
