Question

(03.04 HC)

A woman gives birth to a son who has type O blood. She has type B blood. Which of the following can be concluded from this about her parents' blood types? (1 point)

Select one:
a. One of her parents had at least one O allele.
b. One of her parents had two B alleles.
c. One of her parents had type B blood and the other type O blood.
d. One of her parents had type O blood.

Answer 1

A) One of her parents had at least one O allele.

Step-by-step explanation:

Two alleles are inherited for blood type. Because the woman's son has the O blood type, we can tell that she inherited the B and O alleles. She would have needed to get the O allele from only one other parent. It could either be a recessive allele, like what happened with her son, or from a parent with type O blood altogether (two O alleles).

We cannot tell for sure what blood types her parents had because there are multiple ways to inherit a B and O allele. For example, one parent could have been type AB and the other could have been type O. So, we can only assume what one of her parents' alleles must have been.