Blood Types Problem Set

Problem 6: Do we all have the same biological father?


We were surfing the net for information on how to confirm blood types inherited from our parents. Your home page offered a lot of good, basic information, but since we are non-bio-science types, our understanding is dated back to high school. Could you offer a reference that would be helpful to figure out blood typing. We understand that a ABO matrix is part of it, and we expect it to be technically over our heads - but we're willing to try. Our basic question is: What is the blood type consistency of two parents who are O+ who have 8 children? 2 of 8 are reported to be O+ and O-. Does that seem to be likely?? --John

A. Likely
B. Unlikely
Dr. Hallick's reply:
The parents are either O+/O+ or O+/O-. (We really can't distinguish).

There are three possible crosses:

1. O+/O+ x O+/O- ====> All children are O+

2. O+/O+ x O+/O+ ====> All children are O+

3. O+/O- x O+/O- ====> Children could be either O+ or O-

It is very unlikely that the writer would be able to determine whether his parents are O+/O+ or O+/O-. The best answer to this question would be that, given no additional information, the children could be either O+ or O-.

The Biology Project
University of Arizona
Thursday, October 23, 1997
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