The P{XP} element used for mobilization was located on a first-chromosome balancer Binsinscy; the transposase source was P{Δ2-3}99B, a stable source of transposase on the third chromosome. Dysgenic females were used; from the dysgenic crosses a single new insertion was retained per vial, to avoid premeiotic clusters. Insertions were mapped to a chromosome by standard genetic methods, examined for homozygous viability and used for recovery of flanking genomic sequence.

Markers in stocks (as originally submitted to the BDSC):w¹¹¹⁸.

Flanking genomic sequences were obtained by sequencing of inverse PCR products, and were mapped by alignment to the genomic sequence. For the combined Exelixis lines, 89% could be uniquely mapped to the genome.

Reanalysis of the genomic mapping of most of the combined Exelixis collections (insertions of P{XP}, PBac{PB}, PBac{RB}, and PBac{WH}) was undertaken. After multiple assessments, including sequencing and alignment of inverse PCR products, 16,073 insertions were mapped to unique sites. Of these, 1859 lines were added to the Gene Disruption Project collection.