Massive recombination takes place in the immunoglobin genes during ProB cell differentiation giving rise to a huge variety of antigen receptors. This recombination requires different pieces of DNA to come together spatially. We have applied our statistical mechanics models to experiments performed on this system by Kees Murre and
collaborators at UCSD. The objective is to probe the physical state of the chromatin involved and to determine the presence of extra molecular players that regulate the process.

Schematics of a recombination event between a V and J segment in the immunoglobin locus (C Janeway, P Travers, M Walport, M Shlomchik, Garland Science Publishing).