A system of four basic types (A, AB, B, and O) into which human blood may be classified, based on the presence or absence of certain inherited antigens.
- ‘In the ABO system, the surface antigens of the red cells are determined by three genes, A, B, and O.’
- ‘Antibodies with haemolytic properties are common within the ABO system.’
- ‘Finally, chromosome 2 heterochromatin contains 16 vital genes, as well as the E and Rsp loci of the Segregation Distortion system, and components of the ABO system.’
- ‘Suitable data for testing our predictions are available in primates, for the ABO system and for color vision genes.’
- ‘Blood groups, which are generally classified by the ABO system (so we are all either A, B, O or AB) differ in their distribution in the world.’