Evolution genetic tool kit
Different organisms are actually variations of same theme.Evolution is not playing with bodies but the machinery which makes bodies i.e, Genes.The Homeotic genes encode transcription factors which play very pivotal role in axial pattering in organisms.Hox genes are conserved throughout evolution. Commonality of form among animals was finally understood ,all organisms use same set of genes to build their bodies and these genes are inherited from a common ancestors lived long ago.
Neil Shubin and Sean Carroll discuss homeobox genes, a set of genes that produce basic body parts in all animals. In 1994, Walter Gehring discovered the eyeless gene, which plays a pivotal role in formation of fruit fly eyes. In an experiment, Gehring put a mouse’s eyeless gene into a fruit fly, resulting in normal fruit fly eyes. The same holds true for homeobox genes for wings, legs, even heads. This discovery indicates that animals descended from a single common ancestor that passed along to them a set of homeobox genes, used to build a wide variety of forms from just a few basic body plans.