Final answer:
After gene arrangement in site-specific recombination, the light chain genes are still unique and capable of binding to different antigens. Each differentiated B cell in the human body typically has a unique variable chain.
Step-by-step explanation:
After gene arrangement in site-specific recombination, the light chain genes are still unique and capable of binding to different antigens. The process of DNA recombinase excising and splicing V and J segments in the light chain gene creates a unique variable region in each antibody. As a result, each differentiated B cell in the human body typically has a unique variable chain.