The Yu lab studies DNA recombination and DNA repair in immune cells in association with antigen receptor gene diversification. This includes the site-directed V(D)J recombination that assembles the antigen binding domain of the immunoglobulin (Ig) and T cell receptor genes; and a region-specific class switch recombination (CSR) that changes the Ig constant region. Both events involve DNA double strand break intermediates that, if not repaired properly, can cause chromosomal deletions or translocations.