Genomic organization of the S. cerevisiae Ty elements. Open boxes with arrowheads depict LTRs, which are labeled with their Greek letter designation. Boxes between LTRs denote open reading frames, and they are offset to indicate that they are separated by a +1 frameshift. Conserved coding domains within each open reading frame are as follows: (RB) RNA binding; (PR) protease; (IN) integrase; (RT) reverse transcriptase; (RH) RNase H.