Would appreciate if you were to fully elaborate on what the purpose of a C chain is in genetics?
I believe you might be talking about VDJ recombination which is genetic recombination specific to lymphocytes like T and B cells. The purpose of this recombination is to create a diverse population of immune cells that are specific to a variety of different potential antigens. For antibodies, or mature B cells, the diversity comes from the V or variable regions which are the parts of the antibody that will recognize a particular antigen. The C or constant region on the other hand will determine whether that antibody is an immunoglobulin G, M, A, D or E.
In short, the V region is important for identifying an antigen while the C region is important specifying the type of immunoglobulin or immune cell.
If this was not the C chain that you were referring to, please let me know!