Blood Type Inheritance Chart

ABO Blood Type System

Human blood contains the following antigens and antibodies, forming different blood types:

• Type A blood has A antigens on red blood cells; their serum produces antibodies against B antigens. A person with type A blood can only receive type A or O blood.
• Type B blood is opposite to type A, with B antigens on red blood cells; their serum produces antibodies against A antigens. A person with type B blood can only receive type B or O blood.
• Type AB blood has both A and B antigens on red blood cells; their serum does not produce antibodies against either A or B antigens. Therefore, if antibodies are separated from donor blood before transfusion, AB blood type people are universal recipients. However, they can only donate to people with the same blood type, i.e., AB can only donate to AB.
• Type O blood has neither A nor B antigens on red blood cells. Their serum produces antibodies against both antigens. Therefore, if antibodies are separated from donor blood before transfusion, O blood type people are universal donors. However, they can only receive blood from the same type, i.e., O can only receive O.

Generally, type O is the most common blood type worldwide. However, in some places like Norway, Finland, Turkey, and Japan, type A is more prevalent. A antigens are generally more common than B antigens. AB blood type is the rarest in the ABO system as it requires both A and B antigens. ABO blood type distribution varies by region and ethnicity.

ABO Blood Type Inheritance

Generally, if both parents are type O, children are most likely to be type O; if one parent is type AB, children are unlikely to be type O; parents with A and O types are unlikely to have children with B or AB types, parents with B and O types are unlikely to have children with A or AB types; if one parent is type O, children are unlikely to be type AB.

From a statistical perspective, Professor F. Bernstein of the University of Göttingen, a renowned blood type researcher, stated: "Primitive hominids were all type O, then suddenly mutated into A and B types. Over time, the original O type split into A and B types." The combination of A and B types produced new O, A, B, and AB types. The chart represents the vast majority of cases, though there is a very small chance of pseudo-O type occurring.