Answer:
If a father has a blood type AB and his wife has a blood type O, their children could be a blood type A or B, with a 50/50 chance.
Explanation:
Blood type and heredity are determined by surface antigens on the red blood cell, called A and B. The surface antigens provided by each parent are genetically encoded:
- Blood type A corresponds to the presence of antigen A, and its genotypic expression can be A/A or A/O.
- Blood type B, whose genotype is B/B or B/O, is due to the presence of a gene containing the B antigen.
- AB blood —due to co-dominance— has a gene for A and another for B, with genotype A/B.
- Blood type O, characterized by the absence of surface antigens, behaves as a recessive trait, which only manifests itself in the absence of surface antigens A and B. The genotype is O/O.
In the case posed the father has the blood type AB and the mother the blood type O, so:
- ♂ blood type AB, alleles A|B
- ♀ blood type O, alleles O|O
The crossing can be seen graphically in the diagram:
Alleles A B
O A|O B|O
O A|O B|O
According to this, the offspring of this man and his wife could be:
- Children with blood type A, genotype A|O, 50%
- Children with blood type B, genotype B|O, 50%
