Final answer:
Somatic recombination by B cells contributes to the diversity of antibody genes by rearranging gene segments at the DNA level, creating a multitude of unique antibody molecules with distinct antigen-binding sites.
Step-by-step explanation:
Somatic recombination by B cells plays a crucial role in generating the diversity of antibody genes. This process, involving mutation and recombination of gene segments, takes place during the maturation of precursor cells in the bone marrow that are destined to become B cells. Specifically, the variable region of each antibody molecule is produced through rearrangements of variable (V), diversity (D), and joining (J) segments linked to a constant (C) region. Remarkably, V, D, and J gene rearrangements occur at the DNA level and can create an enormous variety of antibody molecules, with each mature B cell typically possessing a unique variable chain capable of binding to a different antigen.
The constant domain, which is the same across all antibodies, does not bind antigens. Instead, it determines the antibody's class and the immunological functions it will carry out. Once activated, B cells can differentiate into plasma cells that secrete large quantities of antibodies, each with its unique antigen-binding site created through these genetic rearrangements. Ultimately, these mechanisms ensure a broad and versatile adaptive immune response against a vast array of potential pathogens.