Question

The genotypes of a husband and wife are I^AI^B and I^Ai. Among the blood types of their children, how many different genotypes and phenotypes are possible?

• A. 3 genotypes; 4 phenotypes
• B. 4 genotypes; 3 phenotypes
• C. 4 genotypes; 4 phenotypes
• D. 3 genotypes; 3 phenotypes

Answer 1

Answer: (B)

If the genotypes of husband and wife are I^AI^B and I^Ai respectively, then the probabilities of genotypes and phenotypes among their children can be worked out as: Genotype: I^AI^A; I^Ai; I^AI^B; I^Bi. Phenotype: A:AB: B :: 2:1:1. Thus, there are four possible genotypes and three possible phenotypes among the children.