Blonde hair (b) is recessive, and brown hair (B) is dominant.
A parent has brown hair (Bb). Their first child has blonde hair (bb). Their second child has brown hair (BB).
What must the other parent have (hair color and allele combination)?
(1 point)
O Bb, brown hair
Bb, blonde hair
O. BB, brown hair
O bb, blonde hair
The other parent must have the allele combination Bb and brown hair.
The other parent must have brown hair and the allele combination Bb.
To determine the possible combinations for the other parent's hair color and allele, let's look at the information provided.
We know that blonde hair (b) is recessive and brown hair (B) is dominant. The first child has blonde hair (bb), indicating that both parents must contribute the recessive blonde hair allele for this child to have blonde hair.
The second child has brown hair (BB), indicating that at least one parent must contribute the dominant brown hair allele for this child to have brown hair.
Given that the first parent has brown hair (Bb), we already know that one of their alleles must be the dominant brown hair allele (B). Therefore, to have a child with blonde hair (bb), the other parent must contribute the recessive blonde hair allele (b). This means that the other parent must have blonde hair (bb) as well.
So, the possible combination for the other parent's hair color and allele is "O bb, blonde hair."