Nearsightedness is dominant to normal vision and hazel eyes are dominant to blue eyes.A nearsighted woman with hazel eyes who is heterozygous for both traits marries a man with normal vision and hazel eyes.His genotype for eye color is the same as his wife's.Their three children all have blue eyes and normal vision.What is the probability that their next child will have blue eyes and be nearsighted?
A)1/4
B)1/2
C)3/8
D)1/8
E)5/8

Question

Quizplus · Accepted Answer

The woman is heterozygous for both nearsightedness and hazel eyes, so her genotype can be represented as NnHh. The man is normal and heterozygous for eye color, so his genotype can be represented as nnHh.

To determine the probability of their next child having blue eyes and being nearsighted, we need to use Punnett squares.

* N = nearsightedness allele, n = normal vision allele
* H = hazel eyes allele, h = blue eyes allele

|   | Nn    | nH   | Nh    | nh   |
|---|-------|------|-------|------|
| Hh | NHhHh | nHhHh| NhHhHh| nhHhHh|
| hH | NnHh  | nnHh | NhnHh | nnHh |
| hh | Nnhh  | nnhh | Nhnh  | nhhh |

The four boxes highlighted in bold show the possible offspring that have blue eyes and are nearsighted. There are a total of 16 possible offspring, and 2 of them fit the criteria, so the probability is 2/16 or 1/8.

Therefore, the answer is D) 1/8.

Nearsightedness Is Dominant to Normal Vision and Hazel Eyes Are