Question

Multiple successive gene rearrangements at the immu- noglobulin heavy-chain locus

a. increase the likelihood that a functional heavy chain is formed
b. always follow successive gene rearrangement of the immunoglobulin light-chain locus
c. occur after the completion of the second checkpoint in small pre-B cells
d. are not possible because the D segments are removed following the joining between D to J and V to DJ
e. may result in the production of B cells expressing two different types of heavy chain.

Answer 1

The process of successive gene rearrangements at the immunoglobulin heavy-chain locus can lead to B cells with two different heavy chains, showcasing the diversity within the immune response.

Step-by-step explanation:

The question pertains to the process of gene rearrangement during the maturation of B cells. Specifically, it examines the events occurring at the immunoglobulin heavy-chain locus and their impact on B-cell functionality and diversity. The correct answer to the question—Multiple successive gene rearrangements at the immunoglobulin heavy-chain locus may result in the production of B cells expressing two different types of heavy chain—is reflective of the incredible diversity generated during the B cell development process.

This diversity is achieved through V(D)J recombination, a mechanism that leads to the generation of unique antigen-binding sites within the B cell receptor (BCR) and antibodies. Recombination involves the joining of Variable (V), Diversity (D), and Joining (J) segments to form the variable region of the heavy chain. When this process takes place for both chromosomes in a B cell, it can lead to the production of B cells with two different heavy chains.