Octopus and cuttlefish suckers may have evolved by repurposing ancient developmental genes

Cephalopods, like the octopus, have specialized arms and suckers, but how these structures evolved from the simple bodies of their mollusk ancestors remains a mystery. Researchers from the University of Tokyo compared gene activity during embryonic development of cuttlefish, octopus and snail body parts. They found that several genes associated with appendage patterning showed expression along developing cephalopod arms, but no comparable patterns in developing suckers. Developing suckers instead expressed Ets1, a gene associated with early embryonic development in mollusks. The findings suggest cephalopods evolved suckers by reusing existing genes in new ways.