Final answer:
The rearrangement of the light chain joins the V and J regions through a process called genetic recombination, contributing to the immune system's ability to recognize a diverse array of antigens by producing a vast repertoire of antibodies.
Step-by-step explanation:
The rearrangement of the light chain joins the Variable (V) and Joining (J) regions. This process is known as genetic recombination, which is part of the immune system's way of generating diversity in antigen recognition. As germ-line B cells mature, they undergo a DNA rearrangement mechanism in which an enzyme called DNA recombinase randomly excises segments from the light chain gene and these segments are spliced together. This results in a large combination of possible V-J pairings, which allows for the generation of a vast array of unique antibodies, each with a different variable region capable of binding to a distinct antigen. The constant domain of these antibodies remains the same across all antibodies, as it does not participate in antigen binding.