Q18 of 53 Page 29

Mother and father of a person with ‘O’ blood group have ‘A’ and ‘B’ blood group, respectively. What would be the genotype of both mother and father?

Both mother and father are heterozygous for ‘A’ and ‘B’ blood group, respectively.


The person with O blood group is having the genotype to be ii.


In case 1 were Mother is homozygous for ‘A’ blood group and father is heterozygous for ‘B’ their genotypes are respectively IAIA andIBi. These genotypes of parents cannot generate a genotype ii of blood group O.


In case 2 were Mother is heterozygous for ‘A’ blood group and father is homozygous for ‘B’ their genotypes are respectively IAi and IBIB. These genotypes of parents cannot generate a genotype ii of blood group O.


In case 3 were both mother and father are heterozygous for ‘A’ and ‘B’ blood group, respectively their genotypes are IAi and IBi. These genotypes of parents provide two “i” alleles thus it’s possible to generate a genotype ii of blood group O.


In case 4 were both mother and father are homozygous for ‘A’ and ‘B’ blood group, respectively their genotypes are IAIA and IBIB. These genotypes of parents cannot generate a genotype ii of blood group O due to lack of the allele “i” in their gene.

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