V(D)J Recombination

V(D)J Recombination: for the community of immunologists and developmental biologists, the molecular route by which B and T lymphocytes acquire their unique function of affording adaptive immunity. Yet, for many from experienced scientists to trainees it represents a (rather too) sophisticated process whose true insight is excessively demanding. However, when not simply considered as a private ground for a few aficionados, it can be seen as a way of understanding how mature lymphocytes carry on their basic functions. For the group of aficionados which includes this editor it is an elegant paradigm featuring many fascinating evolutionary achievements of which the biological world alone has the secret. These include a subtle biochemical principle most likely hijacked some 470 million years ago from an ancestral gene invader and since then cleverly adapted by jawed vertebrates to precisely cleave and rearrange their antigen receptor (Ig and TCR) loci. This invader would itself have assigned the services of the nonhomologous end joining (NHEJ) DNA repair machinery as well as various DNA polymerases or transferases to work in concert with developmental clues in lymphoid cell lineages to generate an immune repertoire and efficient host surveillance while avoiding autoimmunity.