Frog DNA

In Michael Crichton's 1990 novel Jurassic Park and its film adaptation, gaps in the recovered dinosaur gene sequences are filled with frog DNA. In reality this would not give a true dinosaur, because frogs and dinosaurs are not genetically close.

Jurassic World director Colin Trevorrow pointed out that the franchise's dinosaurs, back to Crichton's Jurassic Park and The Lost World, were all partly made with frog DNA, so none of them were "real" dinosaurs. He used the same idea to answer fans worried about the hybrid Indominus rex, whose own genome includes tree frog DNA, saying it was not very different from the earlier films.