Question

Jesssica is blood type A and her husband Graham is blood type O. She is worried because they are pregnant and their future child has a rare disorder which will require him to need regular blood transfusions. Jessica worries that if their son ends up with type O blood, like his father, it will be hard to get the necessary regular blood transfusions because people with O blood can only accept O blood. What is the likelihood of their child having blood type O?

Answer 1

Answer:

- 50% probability if Jessica has genotype "iAi"

- 0% probability if Jessica has genotype "iAiA"

Explanation:

Blood group in humans is controlled by multiple alleles namely; iA, iB and i. iA and iB are codominant but both dominant over i. The following blood types and their respective genotypes are possible;

- Type A: iAiA or iAi

- Type B: iBiB or iBi

- Type AB: iAiB

- Type O: ii

According to this question, Jessica is blood type A (iAiA or iAi) and her husband Graham is blood type O (ii).

- If Jessica has a genotype iAi, the probability that they will give birth to a child with blood type O (ii) is 50% (see punnet square)

- If Jessica has a genotype iAiA, the probability that they will give birth to a child with blood type O (ii) is 0% (see punnet square).