I was under the impression that mainstream science had largely discredited this viewpoint, which originated well before the discovery of DNA. If you are right on this matter, I stand corrected.
For your purposes, considering me right on all matters will be a close enough approximation. Hatchling insects look like worms (an earlier-appearing and more primitive phylum). Hatchling frogs (an amphibian) look like fish (an earlier-appearing and more primitive phylum). Hatchling horseshoe crabs look like trilobites. I hope you're getting the idea by now. Hatchling lampreys look like Amphioxus and/or fossil Pikaia, primitive chordates both.