The concept of "reverse evolution" is somewhat dicey. The idea of evolution is that mutation and natural selection allow for more advantageous genes to be passed on to the next generation. No one can have the genes for fins suddenly turned on because we don't have them in the first place because they were never passed down to us. As to the rest, while the majority of human DNA matches that of other species (presumably for basic functions such as muscle tissue organization), there is no reason for human DNA to contain sequences specific to other species. For example, Barclay turns into a spider despite the fact that the human genome does not contain anything which would produce compound eyes or silk.