Final answer:
In mice, recombination of V, D, and J gene segments results in a high number of potential heavy chains for antibodies, contributing to a diverse immune response.
Step-by-step explanation:
In the mouse, the total number of heavy chains that can be generated by site-specific recombination events is very large due to the genetic rearrangement involving variable (V), diversity (D), and joining (J) gene segments. Like in humans, these segments undergo site-specific recombination events to generate a diverse repertoire of antibodies. Although the provided data does not specify the exact number of V, D, and J segments for mice, the process of recombination can lead to millions of unique antigen-binding sites due to all possible combinations of these segments for the heavy chains of B cell receptors (BCRs) and antibodies. The constant region, however, remains the same for all antibodies within a specific class.