Final answer:
During a B cell's life, changes in Ig genes occur to generate junctional diversity. These changes involve the recombination and rearrangement of gene segments encoding the light and heavy chain variable regions.
Step-by-step explanation:
In B cells, changes in Ig genes occur during the cell's life to generate junctional diversity.
These changes involve the recombination and rearrangement of gene segments encoding the light and heavy chain variable regions.
For example, in germ-line B cells, the variable region of the light chain gene has multiple variable (V) and joining (J) segments. An enzyme called DNA recombinase randomly excises most of these segments and splices one V segment to one J segment.
Through RNA processing, all but one V and J segment are spliced out, resulting in over 106 possible VJ combinations.
As a result of these gene rearrangements, each differentiated B cell typically has a unique variable chain, allowing for a wide range of antigen recognition and elimination.