Question

A woman with type AB blood has children with a man who has type o blood. What are the chances they will have a child with type o blood?
25%
0%
100%
50%

Answer 1

Answer:

The chance of a woman with an AB blood type and a man with an O blood type having a child with O blood is 0%.

Explanation:

A mother with blood type AB (AB) will pass either antigen A or antigen B to the offspring, while the father with blood type O (OO) will not pass any antigen.

The result of an AB X OO cross would be

Alleles        O        O

A                AO     AO

B                BO     BO

For this reason, the offspring of this couple will be

• Blood type A (AO) 50%.
• Blood type B (BO) 50%.
• Blood type O (OO) none.

Heredity of blood type depends on the presence of surface antigens on the erythrocyte membrane. Blood type O occurs in persons whose red blood cells do not possess surface antigens A or B.

Surface antigens are what determine blood type, so :

• The presence of antigen A determines blood type A.
• Blood type B depends on the presence of antigen B.
• Blood type AB has both antigens.

Blood type O has no antigens, and for blood type O to manifest, it must have both alleles for O.

A mother AB and father O cannot have offspring with blood type O.