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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-8,9T1J/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-8,9T1J/DfP9
female, showing an A9 segment. (J) Posterior cuticle of a wild-type embryo.
(K) Posterior cuticle of an iab-8,9T1J/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.
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