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How can I be O negative?

Ok, my mom is A- and my dad is AB-?? Now, I’ve done alot of researching and I don’t think that it is even possible to have O- with them being A- and AB- is it? Please respond. But serious answers only because this is not a joking matter. Thanks!!



The answers above are not exactly true. that “rare mutation” is a rare AB allele usually found (and then like 1 in 10,000) in person of Asian descent… Your scenerio above AO or AA crossed with AB would produce the following:
AO x AB = 1/2 type A; 1/4 type B; 1/4 type AB
AA x AB = 1/2 type A; 1/2 type AB.
The most likely answer is either you are mistaken about the blood types involved or your father is not who you think.
As a note, I have worked in a hospital blood bank for 10 years. I have never ever seen the AB allele and have only read about it in a medical journal. I have encounted numerous patients over the years who are mistaken about their blood type — I hope that is the case here. Best wishes.


It can happen! Don’t worry – check out this website


Yes, I have read it is possible. It requires a very rare DNA mutation.


Your dad would transmit either the A or the B gene to any of his offspring. Ergo they cannot be blood group O.


I think it is possible without a mutation if you have a grandparent with a type O gene. My daughter has O-neg. and I have AB-pos and her mother O-pos. My mother had O-neg. and it all worked out on a Punnet square, completely normal…


You are correct, it is impossible for you to be O negative if your mother is A negative and your father is AB negative. In this setting there there is some dependance on whether your mother is heterozygous for A (AO) or homozygous for group A(AA). If she is heterozygous, here is the chances of your blood type: 50% chance for A, 25% chance for AB and 25% chance for B. If she is homozygous for A, there is a 50% chance you will be A and a 50% chance you will be AB. The rh factor (negative/positive) is a secondary concern that is trivial. The terms heterozygous and homozygous refer to gene expression of the group A blood type. In this case, I would think it would be imperative to have the blood types of yourself, your mother and your father retested to rule out the possibility of a typing error in the Blood Bank. If the tests come back the same, then I am sorry, but you are not the son/daughter of your father. I would have the retesting performed before panicing though, as a mistake has probably been made somewhere. There is a very very rare instance of mutation that can result in your scenerio, so there’s always hope, I think you have to be of Asian decent though. If it’s correct, you’re a cool scientific find! 🙂


I come from a family of 12, I am a twin, I am O neg, my father was A mother was B-, my twin was B , I can get back to you if you would like me to ask my other sister’s and brother’s what there type is.
But there is no need to get all freaked out, i would call your family physician and ask there attending Nurse the question, you may get the answer you are really looking for.