The term human blood group systems is defined by international society of blood transfusion as systems in the human species where cell surface antigens in particular those on blood cells are controlled at a single gene locus or by two or more very closely linked homologous genes with little or no observable recombination between them and include the common abo and rh rhesus antigen . Human blood groups is a comprehensive and fully referenced text covering both the scientific and clinical aspects of red cell surface antigens including serology inheritance biochemistry molecular genetics biological functions and clinical significance in transfusion medicine since the last edition seven new blood group systems and over . The human abo blood groups were discovered by austrian born american biologist karl landsteiner in 1901 landsteiner found that there are substances in the blood antigens and antibodies that induce clumping of red cells when red cells of one type are added to those of a second type he recognized three groups a b and o based on their reactions to each other a fourth group ab was identified a year later by another research team red cells of the a group clump with donor blood of