Question

BO blood type is controlled by three alleles of a single gene. Blood type O is associated with the recessive i allele. Blood types A, B, and AB are associated with the codominant IA and IB alleles. The pedigree shows the inheritance of ABO blood types in a family.
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​ 51-3534498-1574673251651

​Which two genotypes are possible for the individual indicated with the question mark?
A
ii
B
iIA
C
IAIB
D
iIB
E
IBIB

Answer 1

I can't see the pedigree image you referenced. Could you upload the pedigree or type the blood types (and which individuals they are) for the parents and relevant children around the question-marked individual?

If you prefer to solve it yourself, here’s the method to use:

- Possible genotypes by phenotype:
- Type A = IAIA or IAi
- Type B = IBIB or IBi
- Type AB = IAIB
- Type O = ii
- Use parent → child constraints: each child gets one allele from each parent, so a child’s phenotype restricts which alleles each parent must carry.
- Use known genotypes/phenotypes of other relatives to eliminate options.

If you post the pedigree or list the relatives’ blood types, I’ll work through it and give the two possible genotypes with a short explanation.