DNA Polymorphisms: RFLPS

DNA POLYMORPHISMS: RFLPS

Several new genetic polymorphisms, detected directly at the DNA level, have been de-scribed in the Ig region. These are known as restriction fragment length polymorphisms (RFLPs) because they result from variation in DNA base sequences that modify cleavage sites for restriction enzymes. RFLPs have been described in both the V and C regions. Their significance is under active investigation.

As aforementioned, the most widely used method for determining immunoglobulin allotypes is hemagglutination-inhibition, using antisera derived from fortuitously immu-nized human donors. Because of the scarcity of such antisera, investigations to examine the role of allotypes in immune responsiveness and disease susceptibility have been hampered. Recently, molecular methods that allow the detection of allotypes at the genomic level have been developed, thus circumventing the problems arising from the paucity of antisera.