deletion, Chr12, Masao Kakoki 1 Del(12Bdkrb2-Bdkrb1)1Mki MGI:3710158 B1RB2R-null Bdkrb1<->/Bdkrb2<-> Bdkrb2/Bdkrb1<tm1Mki> http://identifiers.org/mgd/MGI:3710158 Null/knockout