Question
ABO blood groups in humans are controlled by the gene I, It has three alleles - IA, IB and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?
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Three
-
one
-
Four
-
Two
Solution
C.
Four
In ABO blood group system, inheritance of grouping is controlled by a single autosomal gene on chomosome 9 with three major alleles A, B and O (IA,IB and IO). The ABO blood group system has at least 6 genotypes. On the basis of presence or absence of antigens and antibodies, four blood groups have been differentiated - A, B , AB and O blood groups.
