Using only random VDJ recombination, from 40 V, 30 D and 6 J gene segments, the number of possible variable regions of the resulting antibody would be
Using only random VDJ recombination, from 40 V, 30 D and 6 J gene segments, the number of possible variable regions of the resulting antibody would be
Select an option to attempt
Correct Answer: Option D
Explanation
VDJ recombination generates antibody heavy chain diversity by combining one each of V (variable), D (diversity), and J (joining) gene segments. With 40 V, 30 D, and 6 J segments, the number of possible combinations by random VDJ joining =variable regions. In reality, additional diversity arises from junctional diversity (P-nucleotide addition, N-nucleotide addition by TdT) and somatic hypermutation — expanding the repertoire to >10^{11} possible antibodies. This question tests only combinatorial diversity from gene segment selection.