The difference between humans and chimps is all in the junk DNA

[Troglodytes]

Humans and chimpanzees share up to 99% of the same DNA, which is particularly remarkable considering we don't look anything like each other. The reason behind our vast difference in appearance is all thanks to our seemingly useless so-called "junk" DNA.

http://io9.com/5853228/

The discussion at the bottom is interesting too.