Ratio+of+Kappa+to+Lambda+Genes

In mice and humans, there are more kappa genes than lambda genes.

Here is an excerpt from Immunobiology Janeway 6th edition (pg. 131): Two types of light chain, termed lambda (1) and kappa (K), are found in antibodies A given immunoglobulin has either K chains or h chains, never one of each. No functional difference has been found between antibodies having h or K light chains, and either type of light chain can be found in antibodies of any of the five major classes. The ratio of the two types of light chain varies from species to species. In mice, the average K to h ratio is 20:1, whereas in humans it is 2:l and in cattle it is 1:20. The reason for this variation is unknown. Distortions of this ratio can sometimes be used to detect the abnormal proliferation of a clone of B cells These would all express the identical light chain, and thus an excess of h light chains in a person might indicate the presence of a B-cell tumor producing h chains.