An immunoglobulin heavy-chain gene is formed by at least two recombinational events

Abstract
The events of B-cell differentiation can be reconstructed in part through an analysis of the organization of H chain gene segments in differentiated B cells. A mouse Ig .alpha. H chain gene is composed of at least 3 noncontiguous germline DNA segments.sbd.a VH [H chain variable region] gene segment, a JH [H chain joining region] gene segment associated with the C.mu. [.mu. chain constant region] gene segment, and the C.alpha. gene segment. These gene segments are joined together by 2 distinct types of DNA rearrangements.sbd.a V-J joining and a CH switch.