[Gene structure and genetic diversity of immunoglobulins in fish].

The current knowledge concerning the structure of fish immunoglobulin (Ig) genes and the genetic mechanisms in generating fish antibody diversities is reviewed. The heavy (H-) and light (L-) chains of the immunoglobulin are encoded by multigenic loci on separate chromosomes. In different taxa of fish, the Ig genes are organized in different patterns. Fish antibody can recognize various foreign antigens,and the antibody diversity is generated by the following genetic mechanisms:the sequence diversity within the segments encoding the variable domain, the combinatorial diversity of V (D) J segments, the imprecision of rearrangements,gene conversion,somatic hypermutation,and the combination of H- and L-chain.