Is it possible for a couple with certain blood types to produce progeny of all four ABO blood types?

When considering the inheritance patterns of ABO blood types, it is important to recognize that the ABO blood type system is determined by a pair of alleles resulting in four possible phenotypes: A, B, AB, and O. Blood types are inherited following Mendelian inheritance principles where different combinations of alleles from parents can produce various offspring blood types.

The correct answer showcases that a couple, where one partner has type A blood and the other has type B blood, can indeed produce children with all four blood types: A, B, AB, and O. Here’s how it works genetically:

• If one parent is type A, they could have the genotype AA or AO.

• If the other parent is type B, they could have the genotype BB or BO.

When these two parents have children, the possible combinations of alleles could yield:

1. If the first parent is AA and the second is BB, the offspring would be AB (no O type).

2. If the first parent is AO (type A) and the second is BO (type B), the possible offspring could be:

• A (AO from A parent and O from B parent)

• B (BO from B parent and O from A parent)