In humans, photic sneezing (sneezing when exposed to sunlight) and wet ear wax are both the result of dominant alleles, P and E, respectively. If a woman who is unaffected by photic sneezing but is heterozygous for wet ear wax marries a man who is heterozygous for photic sneezing but has dry ear wax, what percentage of their children would likely both sneeze when exposed to sunlight and have dry ear wax?

Question

In humans, photic sneezing (sneezing when exposed to sunlight) and wet ear wax are both the result of dominant alleles, P and E, respectively. If a woman who is unaffected by photic sneezing but is heterozygous for wet ear wax marries a man who is heterozygous for photic sneezing but has dry ear wax, what percentage of their children would likely both sneeze when exposed to sunlight and have dry ear wax?

0%
25%
50%
75%

Answer 1

25%

To determine the percentage of their children who would likely both sneeze when exposed to sunlight and have dry ear wax, we need to consider the possible combinations of their alleles.

The woman is unaffected by photic sneezing (pp) and heterozygous for wet ear wax (Ee). The man is heterozygous for photic sneezing (Pp) and has dry ear wax (ee).

When the alleles are combined:
- For photic sneezing, the possible combinations are Pp or pp (50% chance of being heterozygous or unaffected).
- For ear wax type, the possible combinations are Ee or ee (50% chance of being heterozygous or having dry ear wax).

Therefore, the percentage of their children who would likely both sneeze when exposed to sunlight and have dry ear wax is 25%.