Efficiency and specificity of RNAi knockdown in L. dissortis. Embryos stained with a mix containing ten times diluted egfr probe as an internal control and hh probe (A, B) or wg probe (C, D). (A) Normal embryo where the hh + egfr probe mix detected the expression of both hh and egfr mRNA. (B) hh RNAi embryo where the hh + egfr probe mix failed to detect hh but successfully detected egfr mRNA. (C) Normal embryo where the wg + egfr probe mix detected the expression of both wg and egfr mRNA. (D) wg RNAi embryo where the wg + egfr probe mix failed to detect wg but successfully detected egfr mRNA. (E) Early Limnoporus embryo developing normally. (F, G) dpp RNAi embryos showing the same phenotype. This phenotype was obtained using RNAi against two non-overlapping fragments of dpp. dpp: decapentaplegic; egfr: epidermal growth factor receptor; hh: hedgehog; RNAi: gene knockdown using ribonucleic acid interference; T1, 2, 3: thoracic segments 1, 2, 3.