Thu February 24, 2011 By:

A women having blood group B marries a man having blood group A and they have four offsprings. Two children are having blood group O, one having blood group B and other having blood group AB. i] What are the genotypes of parents ?

Expert Reply
Fri February 25, 2011
Dear student,
The blood group antigens are controlled by an autosomal gene designated I (isohaemaglutinin) which has 3 alleles IA, IB and IO.
Allele IA is dominant over the allele IO and produces type A blood. IOIO produces type O blood. An A type individual can have the genotype IAIA or IAIO. Similarly allele IB produces blood group B, and is dominant over IO. Based on this information, we can deduce that the father is  IAIand mother is IBIO
Only if the parents have this combination of genes, will children with O blood group be formed. This will happen when I of father combines with IO of mother. When IO of father combines with IB  of mother, the child will have blood group B.   Also when IO of mother combines with IA  of mother, the child will have blood group A.
Regards, Team Topperlearning
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