Thus, subtle distinctions are multiplied by the more than 100,000 estimated genes. That is, we share virtually all our genes with apes. Others, but probably only a relatively small percentage, would introduce changes that could substantially alter what the protein does. A single nucleotide difference can alter protein function in such a way that it causes a terrible tissue malfunction. However, many other single-nucleotide changes in the same gene would do nothing harmful at all.
Evolutionary changes are the same way some are neutral, some subtle, and some dramatic.
Add them all together, and they can make quite an impact and account for the huge differences we see among organisms.