Question

The two alleles that determine the blood group AB of an individual are located on.
(A) Two different autosomes
(B) The same autosome
(C) Two different sex chromosomes
(D) One on the sex chromosome and the other on an autosome

Answer 1

Hint: The two alleles of the AB blood group are located on the nonsex chromosome of a cell. AB blood group is an example of codominance for a gene with multiple alleles. AB positive is one of the rarest blood groups in the world.

Complete answer:
The AB blood group results from the inheritance of the two alleles i.e A and B on the long arm of chromosome number 9. The two alleles which in the future determine the blood group is located on the same autosome. The same autosome means the allele is present on the same homologous chromosome at the same locus.

Additional Information: An autosome is a type of chromosome other than the sex chromosome. The blood group is determined by the presence and absence of antibodies and antigens on the surface of RBCs.Blood group AB has both the antigens i.e antigen A and antigen B AND no antibody is present.
Allosome is different from autosome. Allosome is a sex chromosome. DNA in autosomes is collectively known as atDNA or auDNA. Humans contain 22 pairs of autosomes and one allosome pair.
These 22 chromosomes in both males and females look similar. Only the last pair of chromosomes i.e allosomes differ between males and females. Each autosome stores many genes and each gene performs its unique function in the cell.
So, the correct answer is ‘The same autosome’.

Note: Individuals with AB blood group can receive blood from any group but cannot donate blood to any group other than AB. This is the reason the AB blood group is known as universal recipients. Blood group ${ O }{ - }$ is the universal donor as it can donate to any blood group.