Question

The gene I that determines ABO blood groups has three alleles $I^A,I^{B}and{I}^O$ . The correct sequence of dominance of these alleles is

• A. $I^A=I^B>I^O$
• B. $I^A=I^B=I^O$
• C. $I^A>I^B>I^O$
• D. $I^A<I^B<I^O$

Answer 1

The correct option is A

$I^A=I^B>I^O$

ABO blood grouping in human beings is controlled by a gene I which has three alleles- $I^A,I^{B}and{I}^O$. Among these, $I^{A}and{I}^B$ are equally dominant indicating codominance, and they are dominant over $I^O$ or i, which is a recessive allele.