Exhibits variable stability as indicated by (a) their reduced recovery among the progeny of C(1)TM-H mothers, (b) the production of X0 patroclinous sons and (c) the instability of single rings produced by single exchange between the arms of the tandem metacentric.
Generated by exchange between the BS duplication and In(1)dl-49
C(1)TM-H, In(1)sc4LR(1)2R .In(1)w<up>vC</up>+dl-49; position of centromere indeterminate. Linear derivative of the unstable R(1)2, In(1)wvC.