‘Organisers’ in jellies hint at animal origins

Researchers have discovered a new ‘embryonic organiser’ in marine predators called comb jellies (Ctenophora) and successfully transplanted them into sea anemones (Cnidaria). Organiser cells determine an organism’s body axis — a map that plots where various parts of the embryo should develop. After the transplant, the anemones developed a second body axis, complete with extra mouths and pharynxes. The findings support the idea that the emergence of organising activity was a key step in animal evolution, says evolutionary developmental biologist Ulrich Technau.