What separates us from the chimps? For starters, that we are formulating such a question (big brains), voicing the question (speech), and investigating its answer using computers (tool manipulation).
99% of our DNA is identical to chimp DNA (in sequence, let’s not forget epigenetics and post-transcriptional control, the up-and-coming underdogs of biology). Your first thoughts might be that key genetic differences underly appearance (e.g. standing upright) and memory (e.g. remembering an entire spoken language). But researchers in several groups across the U.S. found much more.
Genes undergoing positive selection change more rapidly than those undergoing random (neither-beneficial nor harmful) mutations. So by comparing genomes across several species, scientists identified human genes highly divergent from chimp. The functions of these genes are not fully understood, as always is the case with science.
List of key genes identified:
1. Gene that is turned on during development, the product of which (called a protein) helps to sculpt the thumb from the rest of the hand. This gene helps to explain humans’ increased dexterity over chimps, and thereby the construction of more complex tools and the manipulation of the external world. (Can a chimp tie a shoe-lace? Doubtful.)
2. Two genes in diet: one that breaks down lactose and one that aids with starch digestion in the mouth. A flexible diet means a flexible lifestyle. Nature favors the flexible.
3. Gene involved in the production of speech, on the anatomical level. As an analogy, the violin can’t make music without strings (its anatomy), we can’t say words without our speech anatomy (certain bones and things, I won’t go into details). This one interests me particularly. When I think of language, I think of advanced mental faculty. I think of writing poetry that elevates the soul and composing song that crushes our proverbial fragile frames, not the height of the hyoid bone. Fascinates me to bits.