The transposable element Tam3 of Antirrhinum majus is capable of causing large-scale chromosomal restructuring. It induced a large deletion at the nivea locus, to produce the allele niv-:529. The deletion removed the entire nivea coding region while the element remains intact with the potential to induce further rearrangements. Genetic experiments showed that the endpoint of the deletion (called x) is closely linked to nivea. The DNA sequences of niv-:529, a genomic excision of Tam3 from niv-:529, and the original genomic position of x have been determined. These data suggest that the deletion could have resulted from an abortive transposition or through breakage and religation.