In Some Vertebrates, Such as Rays and Some Shark Species

Multiple Choice

In some vertebrates, such as rays and some shark species, immunoglobulin light chain genes consist of multiple units of already rearranged VJ-C genes, of which one is chosen for expression in a developing B cell. This strategy may have evolved in these organisms:

A) Prior to the evolution of rearranging gene segments requiring somatic recombination in developing B cells
B) Prior to the evolution of the RAG1 and RAG2 enzymes needed for recombination
C) As a mechanism to increase light chain diversity beyond that achieved by the use of rearranging gene segments in humans
D) As a mechanism to increase light chain diversity beyond that achieved the gene conversion process used in chickens
E) As a means to generate a rapid response to common pathogens encountered by these animals