Since humans and chimpanzees share 95% of their genes, why
isn't there a closer resemblance between our physical appearance and that of
the chimpanzees? I take it the answer has something to do with the distinction
between genotype and phenotype, but what exactly is it?

Thank you for your time

Hey Taranu

It may seem at first glance that we do not share many physical traits with other chimpanzees, as well as other apes, despite our close genetic relationship mainly because our brains are wired in such a way that we have a very specific idea of what a human is, and therefore we may tend to over-estimate our perception of "how different is A from B" based solely on external appearance. However, if you take a look to a chimp and a human from an anatomical (and of course genetic) point of view, you will find that we share a myriad of morphological, and even behavioural, adaptations. For example, not very long ago a story hit the news with the observation that chimps give birth in a very similar way to humans ( http://news.bbc.co.uk/earth/hi/earth_ne … 462662.stm ). Also, bear in mind that, regardless or race, you, me,  everyone in this site and the world are approximately 99.9% genetically identical, and surely that does encompass a lot of variation in appearance.

Hope this helps answer your question

I'm not a geneticist and it's been close to ten years since I've studied genetics so perhaps I may be overlooking something (maybe someone else on AAB can help me out if I've got something wrong), but according to the Wikipedia page on the chimpanzee genome (http://en.wikipedia.org/wiki/Chimpanzee_genome_project) and human genome evolution (http://en.wikipedia.org/wiki/Human_evol … great_apes
 the total similarity in the two genomes could be as low as 70%. I should probably ask our resident geneticists if this figure is indeed correct and if so, how did we come to the 95% (or I used to remember 98% from my undergrad days) value?

Anyway, assuming that the similarities are 95%, then the difference of 5% in the human genome would be 5% of 3 billion base pairs = 150 million base pairs. I think that's still quite a lot of genetic difference...