Problem
Analyzing Data
Human Blood Types
Red blood cells carry antigens, molecules that can trigger an immune reaction, on their surfaces. Human blood type carries an A antigen, type B has a B antigen, type AB has both antigens, and type O carries neither antigen. The gene for these antigens has three alleles; A, B, and O.
For a transfusion to succeed, it must not introduce a new antigen into the body of the recipient. So, a person with type A blood may receive type O, but not vice versa.
Another gene controls a second type of antigen, known as Rh factor. Rh+ individuals carry this antigen, while Rh- ones don't. This chart of the U.S. population shows the percentage of each blood type.
|
O+
|
O-
|
A+
|
A-
|
B+
|
B-
|
AB+
|
AB-
|
|
37%
|
6%
|
34%
|
6%
|
10%
|
2%
|
4%
|
1%
|
I. Interpret Graphs: Which blood type makes up the greatest percentage of the U.S. population?
II. Calculate: What percentage of the total U.S. population has a positive Rh factor? What percentage has a negative Rh factor?
III. Infer: Which blood type can be used for transfusion into the largest percentage of individuals? Which type has the smallest percentage of possible donors available?
IV. Predict: Could a person with O+ blood have two parents with O- blood? Could that person have a daughter with AB+ blood? Explain your answers.