A 40 year old female patient complains of excessive bleeding. Patient gives a history of road traffic accident 5 hours ago and had a lacerated wound on lower back region. Blood grouping test reveals presence of antigen A and antigen B. This system for blood grouping consists of 3 major allelic genes which are located on-
ABO system:

This system consist of 3 major allelic genes; those are A, B and O.
They are located on long arm of chromosome 9.
These genes control the synthesis of blood group antigens A and B.
Based on presence or absence of antigen A and Antigen B, blood is divided into 4 groups i.e. A, B, AB and O.
Chromosome 8
Chromosome 9
Chromosome 10
Chromosome 7