In humans, the allele for type A blood and the allele for type B blood show codominance. A person with both alleles has blood type AB. Both A and B dominate type O. A person with an allele for type B blood and type O blood marries someone with an allele for type A blood and type B blood. List the blood types of the offspring they could have and the probability for each blood type in the offspring.
[Hint: In humans, blood types are determined by the type of sugar molecule added to the surface of the red blood cells. The letter for the gene encoding the enzyme that can add this sugar is often designated
1. Often the A and B alleles are written as a superscript to the dominant, upper case l: Iª and 18. The recessive allele, lowercase i, codes for an enzyme that does not add a sugar molecule at all, resulting in Type O blood.]