As per ABO blood grouping system, the blood group of father is B+, mother is A+ and child is O+. Their respective genotype can be A. IBi / IAi / ii B. IBIB / IAIA / ii C. IAIB / iIA / iBi D. IAi / IBi / IAi E. iIB / iIA / IAIB Choose the most appropriate answer from the options given below.
Answer: (D) A only. Answer: (D) A only Solution: A child with blood group O has genotype ii, so each parent must carry an i allele.
- A.B only
- B.C & B
- C.D & E only
- D.A only✓
Correct Answer
(D) A only
Solution & Explanation
Answer: (D) A only Solution: A child with blood group O has genotype ii, so each parent must carry an i allele. A B-group father who can pass i must be IBi, and an A-group mother who can pass i must be IAi. Thus father/mother/child = IBi / IAi / ii, which is statement A only. Statements with IBIB or IAIA cannot give an O (ii) child, so option (d) is correct. NCERT Reference: NCERT Class XII, Ch 4, p.61, lines 20-25: "The gene (I) has three alleles IA, IB and i. The alleles IA and IB produce a slightly different form of the sugar while allele i does not produce any sugar." ... "IA and IB are completely dominant over i"