Question

For the following mother-child combinations, indicate which blood types could not have been the father's.

1. Type O mother, type B child
2. Type B mother, type A child
3. Type AB mother, type B child

Answer 1

In cases of Type O mother with type B child, and Type B mother with Type A child, the father cannot have type O blood. For a Type AB mother with a type B child, all blood types are possible for the father.

Step-by-step explanation:

Inheritance of Blood Types

The question revolves around the inheritance of ABO blood types and which blood types a father could not have, given the mother and child's blood types. In each case, we consider the ABO blood groups' inheritance patterns to deduce incompatible paternal blood types.

• Type O mother, type B child: The father cannot be type O because the type B child must have inherited the IB allele from the father.
• Type B mother, type A child: The father cannot have blood type O because the type A child must have inherited the IA allele from the father.
• Type AB mother, type B child: All blood types are possible for the father's blood type since the mother has both IA and IB alleles.

It's important to note that in each case, the mother must have passed on one of her alleles to the child, and we determine the father's potential blood types based on what allele is missing in the child that must have come from the father.