Figure 1.

The genomic region encompassed by the extended P element. (A) The structure of the two P elements used to construct the extended P element is shown. The two closely linked P elements (3DP and 5DP) used for the construction of the extended P element contain the bacterial orgin of replication (ori), the bacterial ampicillin resistance gene (amp) and LacZ gene, and the Drosophila white gene, as well as the 5′ and 3′P element ends 3′P and 5′P (Haenlin et al. 1985). Dashed lines outline the regions of the P elements deleted during the production of half-P-element derivatives. (B) Position of P1 genomic phage in the 66D region used in this study. Uncertainty in the endpoints of P1 genomic clones are shown in dashed lines. (C) Genomic DNA in the 66D region (shown as a solid line) including chromosomal orientation (distal and proximal to the centromere) and the location of sequence tagged sites (sts) in the region, shown as solid circles. (D) Extent of two overlapping genomic λ phage walks through the region, used to characterize the extended P element further, are shown (Spradline 1981; Ish-Horowitz et al. 1985).