 Many of these organisms share the same structural genes for bodybuilding proteins like collagen and enzymes, but biologists had expected that each group of animals would have its own rules of development.The surprise of evo-devo is that the shaping of bodies is controlled by a rather small percentage of genes, and that these regulatory genes are ancient, shared by all animals.The giraffe does not have a gene for a long neck, any more than the elephant has a gene for a big body.