The researchers then showed that the difference between the human and chimp versions of the enhancer result from a difference of only 13 nucleotides, a far larger number of changes than would be expected had the mutations been the result of drift rather than selection. The location of enhancer activity highlights the importance of the difference. Our hands, with their opposable thumbs, our feet, evolved for bipedal locomotion, and our throats, which allow us to speak, make up three key differences between humans and all other apes. Because of its role enhancing the genes that regulate the development of those regions, the evolution of this gene enhancer must have been a key step in the evolutionary separation of the human/chimpanzee common ancestor. Furthermore, by following the presence of this particular gene enhancer, researchers should be able to locate which genes are responsible for our differences from chimps and when they evolved. Mapping out humanity's divergence from apes? Not bad for a bunch of DNA once thought of as junk.