The genotypes of a Husband and Wife are IAIB and IAi. Among the blood types of their children, how many different genotypes and phenotypes are possible?
- 4 genotypes ; 3 phenotypes
- 4 genotypes ; 4 phenotypes
- 3 genotypes ; 4 phenotypes
- 3 genotypes ; 3 phenotypes
Answer
(1) 4 genotypes ; 3 phenotypes
Solution
Cross: IAIB IAi
The husband gives gametes IA and IB, and the wife gives IA and i, so the children can be IAIA, IAi, IAIB or IBi, i.e. 4 genotypes.
Of these, IAIA and IAi give blood group A, IAIB gives blood group AB (IA, IB co-dominant) and IBi gives blood group B.
∴ 4 genotypes and 3 phenotypes (A, AB, B).
Answer: (1)