Transgenic Xenopus laevis strain expressing ubiquitous red fluorescence. F1 animals of the tom3 strain at the neurula (A), larval (B) or froglet stage (C) seen with the red fluorescence filter set. D: Isolated tissue of a control froglet (left) and a froglet of the tom3 strain (right) seen in normal light. E: Same tissue samples seen in the red fluorescence filter set. F-H: Isolated muscle of a froglet of the blue fluorescent C5 strain  (left) and of the red fluorescent tom3 strain (right) seen in normal light (F), with red fluorescence filter set (G), or blue fluorescence filter set (H). Scale bars equal 1 mm.