Fig. 5. ds-RNA-mediated genetic interference. Cuticle preparations showing denticle belts corresponding to abdominal segments A1-A8 and thoracic segment T3. Anterior is to the left. (A) Wild-type injected with buffer only. T3 and A1-A8 denticle belts are clearly visible. (B) run^YP17. This hypomorphic allele produces a weak segmentation phenotype. A deletion of the lateral edges between the A2/A3 denticle belts results in the curved appearance of these belts. Deletion of the naked cuticle between the A4/A5 and the A6/A7 denticles is also evident. (C) run^XD106. This null allele produces a severe segmentation phenotype. Large deletions between the A2/A3, A4/A5, and A6/A7 denticle belts are apparent. These deletions result in mirror image duplications of the corresponding denticles. (D-F) Three independent examples of wild-type embryos injected with double stranded RNA corresponding to the run gene (ds-run). In each example there is a complete deletion of the naked cuticle between A2/A3, A4/A5, and A6/A7 which results in a mirror image duplication of the remaining denticles. This is the same phenotype as that seen in null alleles of run (compare with C). (G-I) Three independent examples of wild-type embryos injected with ds-Bgb. No perceptible alteration of the segmentation pattern is evident. These animals are indistinguishable from those injected with buffer (compare with A). (J-L) Three independent examples of wild-type embryos injected with ds-Bro. Defects in the segmentation pattern are similar to those seen in hypomorphic run mutants (compare with B). (M-O) Three independent examples of wild-type embryos injected with a mixture of ds-Bgb and ds-Bro. An extremely strong segmentation phenotype identical to that seen with null alleles of run (compare with C) and wild-type embryos injected with ds-run (compare with D-E) can be seen. Thus, although injection of ds-Bgb did not affect segmentation, and injection of ds-Bro produced a mild segmentation defect, injection of a mixture of both ds-Bgb and ds-Bro had a synergistic effect on the pattern of segmentation.