Probable top-strand cleavage sites for the R1 element insertions. Dots indicate for all R1 elements the last nucleotide at the 5' junction that corresponds to the upstream 28S sequence. In instances where multiple copies of an element within a species had identical junctions, the number of genomic copies was estimated by dividing the number of traces by the fold coverage of the genome sequencing project. Arrows show the location of the insertion site (bottom-strand cleavage used for TPRT). The different types of junctions diagrammed in Figure 7 are given different symbols. (a) Ancestral type R1 elements. Data derived from D. ananassae A, D. mojavensis, D. pseudoobscua and D. willistoni. (b) Melanogaster-type R1 elements. Data derived from D. melanogaster, D. sechellia, D. simulans and D. yakuba.