Robust, high resolution formaldehyde-based in situ hybridization method for the interrogation of planarian regeneration. Schmidtea mediterranea specimen after head and tail regeneration labeled by combining immunofluorescence and double fluorescent in situ hybridization. Riboprobes for Smed-porcn-1 (gastrovascular system) and Smed-slit (midline cells) are shown in blue and green, respectively, while mouse anti-a-tubulin antibody (brain, ventral nerve chords, pharynx, flame cells) is shown in red/magenta. Images obtained by Sarah Elliott and Kyle Gurley, University of Utah. See Pearson et al., Developmental Dynamics 238:443-450. Developmental Dynamics, 2009. © 2009 Wiley-Liss, Inc.