Polymorphism map of FRT versus EP strains. The locations of 495 SNP marker loci that discriminate between FRT and EP strains are shown. For each arm, the right scale shows the approximate extent of each cytological division, whereas the left scale indicates the precise location (in Mb) of each marker on one of the ten contigs of at least 1 Mb in Release 2 of the Drosophila genome sequence. The locations of the proximal FRT and distal EP insertions are shown. Arrowheads indicate markers for which PLP assays have been established. Restriction endonucleases for verified RFLPSNPs are also indicated.