Here's a formula which should be easy for you to remember:
Each animal species has a characteristic chromosome number. We humans have 23 pairs of chromosomes. Please explain these "accumulated modifications" that got us from 22 or 24 or whatever pairs to 23.
It's not as if humans (or other animals) are never born with a different number of chromosome pairs, but none of these humans (or other animals) ever have grandchildren; which is sort of a bummer for anyone who believes in Darwinian evolution as you seem to.
ML/NJ
If every species was created separately, why should there be any DNA in common at all between chimpanzees and human beings?