The amino acid sequence of the light chain variable region of a canine myeloma immunoglobulin: Evidence that the vk subgroups predated mammalian speciation

The complete amino acid sequence of the variable region of a kappa light chain derived from a canine myeloma immunoglobulin is presented. The sequence is more than 80% homologous to the human kappa variable region Cum the prototype of the human V_KII subgroup and is the first example of a non-human kappa chain which can be easily classified as a subgroup other than V_KI. The finding confirms a previous prediction that genes encoding kappa subgroups predated mammalian speciation.