Question

Mr. and Mrs. Black had a baby last night in the local hospital. At around the same time, Mr. and Mrs. White also had a baby in the same hospital in the room adjacent to the Blacks. Both babies were girls, both weighed about the same, and looked very similar.

The following day, a nurse brought the babies from the nursery to the new parents, but Mr. and Mrs. Black insist that they got the wrong baby! To test that, everybody's blood was drawn to establish the blood types. Here are the results:

Mr. Black has blood type O Mrs. Black has blood type AB The baby in Black's room has blood type O

Mr. White has blood type A Mrs. White has blood type B The baby in White's room has blood type A

Try to solve this situation using what you have learned about the alleles and genotypes coding for these blood types to establish if the Blacks' and Whites' babies were switched. Use the Punnett squares to prove your point.

Have fun with it!

Answer 1

Mr black blood group O

Mrs black blood group Ab

Mr black(allele left to right) Mrs black(allele down)	Io	Io
Ia	AO or IaIo	AO or IaIo
Ib	BO or IbIo	BO or IbIo

So probable blood group of kid is A or B

Now Mr.white blood group A so probablility of genotype Ia Ia or Ia Io

Mrs white blood group B

So probability of genotype

Ib Ib or Ib Io

Probability of child

Mr white left to right Mrs white down	Ia	Ia
Ib	IaIb	IaIb
Ib	IaIb	IaIb

So probable blood group is AB

In case 2

Mr white left to right Mrs white down	Ia	Io
Ib	IaIb	IbIo
Io	IaIo	IoIo

If heterogygous condition exist all 4 pehotype of blood group are possible

A B AB 0

Baby In room of black has blood group O which is not possible

So baby get switch between them