In the case below, were the babies switched? How do you know whether they were or they weren’t?
- It was suspected that two babies had been exchanged in a hospital. Mr. and Mrs. Jones received baby #1 and Mr. and Mrs. Simon received baby #2 Blood typing tests on the parents and the babies showed the following:
Mr. Jones: Type A
Mr. Simon: Type AB
Mrs. Jones: Type O
Mrs. Simons: Type O
Baby #1: Type A
Baby #2 Type O
The alleles for A and B are codominant and the allele for O is recessive. In order to produce an individual who is type O, each parent must contribute an O allele. The only parents who could possibly do that is the Jones couple. That is because Mrs. Jones who is type O would supply one O allele and Mr. Jones, who is type A had to be heterozygous for type A meaning he has one A and one O allele in his genotype. He supplied the second O allele and the offspring was type O. The Simons couple could not be the parents of baby #2 since Mr. Simon can only contribute an A or B allele since he is type AB and could never produce an offspring with type O.
Therefore, the babies were accidentally switched at birth.