1. Multiple Alleles and
Human Blood Types

2. Many human traits are controlled by a single gene with just two alleles EX: widow’s peak, hair on fingers, dimples, cleft chin, ear lobes freckles

3. Some human traits are controlled by multiple alleles
Even though there are more than two alleles for the trait, a person can only have two alleles for the trait

4. Blood Type The 4 human blood types are: A, B. AB & O
The alleles for blood type are
A, B, & O

5. A-Dominant to O, Codominant to B B-Dominant to O, Codominant to A
Blood Type Alleles
A-Dominant to O, Codominant to B
B-Dominant to O, Codominant to A
O-Recessive to both A & B

6. Genotype Phenotype AA, ao Type a bb, bo type b ab type ab oo type o

9. Problems In the maternity ward, Mrs. Bright and Mrs
Problems In the maternity ward, Mrs. Bright and Mrs. Light shared a room. When they were ready to go home, Mrs. Bright insisted that she had been given the wrong baby. The babies looked very much alike, and unfortunately, no one could find a record of the babies’ footprints. Hospital officials told Mrs. Bright she was mistaken and sent her and the baby home. Mrs. Bright eventually asked the hospital to perform identification tests. Several weeks later, blood tests showed the following data.

10. Mrs. Bright-Type AB Mr. Bright-Type O Baby at Bright’s home-Type O Mrs
Mrs. Bright-Type AB Mr. Bright-Type O Baby at Bright’s home-Type O Mrs. Light-Type A Mr. Light-Type a Baby at Light’s home-Type A

11. Were the babies “switched at birth” ?

12. Suppose a father of blood type B and a mother of blood type O have a child of type O. What are the chances that their next child will be blood type O? Type B? Type A? Type AB?

13. A woman who has type A blood has a child with type AB blood
A woman who has type A blood has a child with type AB blood. She is suing a man for child support who has type O blood. Is she suing the right man?

14. Can blood type prove paternity? What can it prove?