One fatefull day approximately 5 millions years ago there was a serious domestic dispute in a small group of primates. A section of the group stomping off grunting something to effect that they were sick and tired of the stuffy old way things had been done and want to try something new, which in fact they did. They tried being humans and it worked. Today we are clearly the most successful of the primates with most of the others on the verge of extinction but how much have we diverged from our primate cousins?

The answer is not that much really. Scientists estimate that humans and chimps share about 99.2% of their respective genomes but the really interesting bit is to look at those areas in which we are different. These are pointers to the different evolutionary paths that we have taken.

Michele Cargill of the biotech company , Celera Diagnostics in Alameda, California has done this comparison and has discovered that the most significant differences are in the areas of smell, hearing and the way we digest protiens. She compared the sequences for more than 7,500 human, chimpanzee and mouse genes, compiled by the genome projects for each species, the mice providing a useful indicator by which she could eliminate generic mammalian genes. Differences were found in around 50 genes tied to smell with many of the human equivalents demonstrating little functional value, reflecting the lack of importance of smell to our species.

Twenty-one genes linked to hearing also displayed differences which she hypothesised may be linked to the development of language. Eighty genes used to digest proteins also differ between chimps and humans probably arising from the differing diets of the two species over the period since we diverged.

Read more in Nature here.