The genes for ABO blood group is located on _____________.
ABO blood group in human beings is first discovered by Landsteiner. The fourth blood group, AB was discovered by de Castello and Steni. Bernstein showed that these groups are controlled by three alleles – IA,IB and IO/i. These alleles are autosomal and follow the Mendelian pattern of Inheritance. These alleles are present on the 9 chromosome of the body.
So, the correct option is ‘chromosome 9’.