Which piece of evidence explains the cause of blue eyes?
A
A dominant gene will often produce enough of its protein on its own to result in its special trait.
B
So when it is paired with the recessive allele, the physical result is the same as if it were paired with another dominant allele.
C
If the genes that control melanin production in the eye are recessive, then the protein will be turned off — there will be zero dosage — resulting in eyes with no melanin.
D
However, the dosage is a big factor, which is why we often see eye color presented as a simple trait, like Mendel's pea height.