Question

The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because ‘O’ in it refers to having
A.No antigens A and B on RBC’s
B.Other antigens beside A and B on RBC’s
C.Overdominance of this types on the gene for A and B types
D.One antibody only either-A or anti-B on the RBCs

Answer 1

The principle of dominance states that, when two genes are found in an organism one of them masks the presence of another one, in other words one gene is dominant and stops the expression of the other gene.

Complete step by step answer:
To solve this question, we must understand ABO blood grouping.. The ABO blood grouping controlled by gene I, and has three alleles IA, IB, and i. The allele IA and IB form different forms of sugar and allele i does not form sugar. The allele IA and IB are dominant over i, therefore when IA and i is present only IA will be expressed and same in case of IB and i. but when IA and IB present together both are expressed at the same time. Because of this there are three different alleles that have six different genotypes and four different phenotypes. For example, a man with blood group ‘A’ marries a woman with blood group ‘B’, then the with A blood group has encoded by gene IA and has antibody for B and the woman with B blood group has B antigen with gene IB and antibody A. When both of them get married, the blood group of the offspring can be A, B, and AB, as they have both A and B antigen, and A and B antibodies.
Now, the ABO blood grouping is named so as O refers here no antigens on RBCs. A blood group has A antigens and B antigen has B antigens, while B blood groups have both A and B antigens on RBCs.
Thus, the correct option is ‘A’. No antigens A and B on RBC’s.
Additional information:
Co-dominance is the phenomenon in which both the alleles in a heterozygote express themselves at the same time. Co-dominance is observed in blood grouping of humans

Hence the correct answer is option(A)

Note: The blood grouping is also an example of multiple alleles as more than two alternative forms of gene found on a particular locus are considered as the multiple alleles. It is formed as a result of repeated mutation of the same gene but in different directions.