The Hox genes Ultrabithorax and abdominal-A specify three different types of abdominal appendage in the springtail Orchesella cincta (Collembola)

Table 2 Efficiency of Oc-Ubx and Oc-abd-A silencing by parental RNAi in Orchesella

dsRNA	Females		Larvae collected	Homeotic phenotype
dsRNA	Injected	Survived	Larvae collected	None	Weak	Strong
egfp	96	80 (83%)	415	415 (100%)	-	-
MalE	27	20 (74%)	195	195 (100%)	-	-
Oc-Ubx	77	52 (67.5%)	249	58 (23.5%)	44 (17.5%)	147 (59%)
Oc-abd-A	99	67 (68%)	622	140 (22.5%)	205 (33%)	277 (44.5%)
Oc-Ubx + MalE	27	12 (44%)	98	41 (42%)	15 (15%)	42 (43%)
Oc-abd-A + MalE	42	26 (62%)	173	75 (43.5%)	32 (18.5%)	66 (38%)
Oc-Ubx + Oc-abd-A (injected once)	49	37 (76%)	141	7 (5%)	107 (76%)	27 (19%)
Oc-Ubx + Oc-abd-A (injected twice)	102	47 (46%)	43	4 (9.5%)	6 (14%)	33 (76.5%)

Eggs were collected for 10 days after female injections. All larvae hatched; we did not count the unfertilized eggs, which are occasionally laid by RNAi, control and non-injected females and always represent less than 1%. dsRNAs for egfp and MalE genes served as controls. The table shows only a part of our experiments where we scored and counted all the larvae. In total, we observed offspring from 239, 99, 316, 120 females injected with egfp, MaleE, Oc-Ubx and Oc-abd-A dsRNA, respectively; we always saw only the phenotypes specific for each treatment. Homeotic phenotypes: strong: transformed appendages morphologically similar to their normal counterparts; weak: appendages with signs of transformation, but malformed, for example, A1 and A4 partially fused proximally in Oc-Ubx(RNAi) or Oc-abd-A(RNAi), A3 blister-like in Oc-abd-A(RNAi), elongated, non-segmented, partially fused proximally in Oc-Ubx + Oc-abd-A(RNAi).

ISSN: 2041-9139