Question

In this question, consider eggs from a human with type O blood and sperm from a human with type AB blood. These individuals produce children, some of which have type A blood and some of which have type B blood, but none have type O blood. a. What is the genotype of the individual who produced the eggs? What is the genotype of the sperm?

Answer 1

The genotype of the individual with type O blood is ii, and the genotype of the individual with type AB blood is IAIB. The children with type A and type B blood would have the genotypes IAi and IBi, respectively, as the parents can only pass on the i allele from the type O parent and either the IA or IB allele from the type AB parent.

Step-by-step explanation:

The student's question revolves around the inheritance of ABO blood types when one parent is type O and the other is type AB. Since children have type A and type B blood but none have type O blood, we can deduce the following genotypes:

• The individual who produced the eggs with type O blood must have the genotype ii, as type O is characterized by having two recessive alleles.
• The individual who provided the sperm with type AB blood has the genotype IAIB, since both alleles are expressed in type AB blood.

As for the children's genotypes, those with type A blood could have either IAi or IAIA, and those with type B blood could have either IBi or IBIB. However, the presence of type A and type B children and absence of type O children rule out the possibility of the IAIA and IBIB genotypes in this case.