The locus was interrupted by the replacement of the Dbeta2-Jbeta2 gene cluster with a loxP site. Gene segment rearrangements on this allele are restricted to the Dbeta1-Jbeta1 gene segment cluster, which contains one Dbeta (Dbeta1) and six Jbeta (Jbeta1.1-Jbeta1.6) gene segments. (J:119552)