Chordate Classification Origin of chordates
The process of paedomorphosis, where juvenile features are retained in the adult, is the proposed mechanism. Garstang, Walter 1894. Zoologischer Anzeiger' '17', p122.Garstang, Walter 1928. Embryos and ancestors'. 3rd ed, Oxfor, The evolution of chordates, p76. Genome analysis does show that the tunicates are the closest living relatives of vertebrates.