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Biology/exceptions in blood types


I am an Asian,my dad's mom and dad are cousins, my parents are cousins too. (intermarriage) Me and my brother both have O+ blood type, my dad has O+, my mom has AB+. How is this possible? I am sure this is an exception and we are NOT adopted. Can you please explain it to me and also send me reliable links or sources that can proof it? thank you very much!

Hi Refah
The genetics behind human blood typing is so exact that it is accepted as evidence in a court of law when determining family relationships.  Type O blood is recessive which means that you would have to inherit two genes for type O blood. We can forget the + Rh factor here. My only explanation here is that you mother has been mistyped. She cannot have an AB type, she must have a gene for Type O especially since your brother is also Type O.
 It is also a fact that most Asians are Type O and only 7% are AB
 You can find proof of this in any information about ABO blood genetics
 This can be solved with a simple blood test on your mother


If you are not adopted then the only other explanation that I can give is that you have been typed wrong. You have to be A or B. The cousin marriages have nothing to do with blood types


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Walter Hintz


Science teacher for over 50 years. MSc. in biology. I can answer questions in general biology, zoology, botany, anatomy and physiology and biochemistry.


I have a MSc in biology and have been a science teacher for over 50 years. At present I am a faculty member at a college and a science consultant at seven catholic schools.

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