Fig. 3 - Supplemental 1

Sterlet Acvr2a is expressed in developing neuromasts and ampullary organs. In situ hybridisation in sterlet for the type II receptor gene Acvr2a. Black arrowheads indicate examples of developing neuromasts; white arrowheads indicate examples of developing ampullary organs. For trunk images, boxes on low-power insets delineate the regions shown. (A,B) At stage 37, there is no detectable Acvr2a expression. (C,D) At stage 38, faint expression is seen in developing neuromast regions. (E–J) At stage 40 (E–G) and stage 42 (H–J), Acvr2a is expressed in developing ampullary organ primordia and neuromasts on the head (E,F) as well as in the migrating lateral line primordia and neuromasts on the trunk. (K–M) By stage 45, only faint Acvr2a expression remains around some ampullary organs on the head (K,L), although expression is still seen in the migrating primordia and neuromasts on the trunk (M). Abbreviations: e, eye; prim, migrating lateral line primordium (primI, primary; primII, secondary; primD, dorsal); S, stage. Scale bar: 250 μm.