Analysis of sh-m6233, a mutation induced by the transposable element Ds in the sucrose synthase gene of Zea mays

The unstable allele sh‐m6233 caused by insertion of the transposable element Ds into the sucrose synthase gene of maize, was cloned. The mutation is caused by the insertion of an ˜4 kb DNA segment, consisting of two identical Ds elements of ˜2000 bp length, of which one is inserted into the center of the other in inverted orientation. This structure is, at the level of restriction mapping and partial DNA sequencing, identical to the double Ds element found in a larger insert in the mutant allele sh‐m5933. 8 bp of host DNA are duplicated upon insertion. In a revertant, a 6‐bp duplication is retained.