Mutations in full-length Ty1 and Ty2 elements. Open boxes with arrowheads depict LTRs (not drawn to scale), and lines depict theGAG and POL reading frames (drawn to scale). For the deletion mutants, sequences and numbers in parentheses below each element correspond to the full length sequences of Ty1 (YBRWTy1-2) or Ty2 (YCLWTy2-1), which sandwich the sequence present in the deleted element; underlines mark the extent of sequence duplication at the deletion break points, and arrowheads correspond to the precise position of the breaks. For the duplication mutant, stippled boxes indicate the duplicated sequences, which are flanked by the dinucleotide AC.