Figure 7. Distinctive P Elements Revealed by Re-screening a Random Sample of P Element Insertion Sites in Natural Populations for Four Genes, Hsp23, Hsp27, Hsrω, and Hsp70 .

The P element insertion sites were selected from Gene Set I. A plus sign (+) indicates successful PCR amplification with one primer complementary to the focal gene and another complementary to a unique sequence in the P element (top), and thus reports the size and orientation of the P element; a minus sign (−) indicates no amplification. Table S7 provides sequences of these primers. At each insertion site in a population, one to six distinctive P elements segregated; these are designated a–f. For Hsp23, Hsp27, and Hsrω, nine insertion sites shared by two or more natural populations (indicated by boxes) and 17 unique insertion sites were re-screened. Amplicons that share a symbol (filled square [█], filled triangle [▴], filled circle •], etc.) occurred at the same integration site in different populations and were indistinguishable by size or orientation. For Hsp70, a five-copy gene in natural populations [17], the specific gene of insertion was not determined; thus, each distinctive amplicon (a–f) could represent insertion(s) at the same site in one to five of the Hsp70 genes. For population codes see Figure 1.

ORF, open reading frame.