Fig. 7.

Southern blot detection of lethal chromosomal lesions, the breakpoints of which map to the region encoding Dmca1A.Goralski (1985) localized breakpoints of inversion- and deletion-containing chromosomes to a relatively small genomic interval within the cytogenetic region called 11A2 by RFLP detection with multiple restriction enzymes. To confirm elements of these findings, we prepared genomic DNA from In(1)N66 and Df(1)HF368flies heterozygous for the In(1)FM7 balancer chromosome, from homozygous In(1)FM7 flies, or from a wild-type strain (Canton-S). DNA in lanes 1–3 was subjected to restriction digestion with HindIII, in lanes 4–6with BamHI and KpnI, and in lanes 7–9with HindIII and KpnI (following Goralski, 1985). The blot was probed with genomic phage clone 320 (cf. Goralski, 1985), which contains a portion of the Dmca1A ORF extending approximately from transmembrane domains IS5 to IIS5 (see Fig. 1). The novel restriction fragments present in lanes 1, 4, and 7 are as originally detected by Goralski (1985); the size of these fragments (in kb) is indicated in the left margin of the figure.