Figure 3.

Confocal micrographs of the first and second abdominal segments of D. sechellia (a) are similar to those of a hybrid between a D. melanogaster svb¹ mutant and D. sechellia (b). In contrast, a hybrid of wild-type D. melanogaster and D. sechellia (c) displays a cuticular pattern similar to D. melanogaster (see Fig. 1). The D. melanogaster svb¹ mutations leads to complete loss of denticles and hairs on the dorsal surface (not shown) and loss of most denticles on the ventral surface (d). [In some svb¹/D. sechellia larvae, small patches of hairs in the middle of naked cuticle were occasionally observed (b). Such hairs were never observed in hybrid backcrosses and in crosses between svb deficiencies and D. sechellia, suggesting that svb¹ is not a complete loss-of-function allele.] Anterior is up.