Fig. 4. Embryonic and adult phenotype of iab-8,9 mutations. T indicates tergite (dorsal part of an abdominal segment) and S indicates sternite (ventral part of an abdominal segment). Numbers after T or S refer to the abdominal segment. The posterior dorsal abdomen of DfP9/+ females (A; An stands for analia) and males (C), and the ventral abdomen and genitalia of adult wild-type females (E) and males (G) are compared with those of iab-8,9^T1J/DfP9 females (B, dorsal; F, ventral) and males (D, dorsal; H, ventral). The genitalia of DfP9/+ males and females are similar to those of wild-type animals, except that male genitalia of DfP9/+ flies are rotated. Three main differences can be observed in iab-8,9 mutations with respect to wild-type or DfP9/+ adults: (1) they have an A8 (T8 in B and D), which is much reduced and with just a few bristles in DfP9/+ females (A; the arrowhead indicates the T8 bristles) and absent in DfP9/+ males; (2) wild-type female genitalia (FG in E) are replaced by a sternite in these mutations (S8 in F); and (3) there is an incomplete eighth sternite in the male of iab-8,9 mutations (S8 in H), which is absent in wild-type (G) or DfP9/+ males. Male genitalia (MG in G) are replaced in iab-8,9 mutations by an unidentified tissue (H). In iab-8,9 adults, segments anterior to A8 show only the haploinsufficient phenotype of DfP9: a small T7 (C,D) and some bristles in the S6 (H). The arrow in B indicates a small A9 segment. (I) Posterior abdomen of an iab-8,9^T1J/DfP9 female, showing an A9 segment. (J) Posterior cuticle of a wild-type embryo. (K) Posterior cuticle of an iab-8,9^T1J/DfP9 embryo, showing transformation of the A8 into a more anterior segment, revealed by the trapezoidal form of the A8 denticle band (rectangular in the wild type), the space between the A8 denticle belt and the anal pads (AP) and the absence of posterior spiracles (PS). Occasionally, a small A9 can be observed in these embryos.

Return to article