... The human and chimpanzee genomes differ by just 1.2% between the coding genes...
... "What we have now done is systematically looked at gene activity in the brain of chimpanzees, humans, orang-utans and macaques and when we compare them the surprising finding is that we actually find quite a lot of differences.
"And in any particular part of the brain about 10% of our gene activity differs from those of chimpanzees," said Dr Paabo.
We expected large differences between chimp and human brains. How can that occur given almost identical genomes? The trick is modulation of gene expression; an eightfold amplification of coding distinctions. I doubt this answer suprises any geneticist, but the research is fascinating.
Since individual people are very similar (more than 99% identical genes), and yet individual genetically determined abilities are quite different, gene amplification perhaps accounts for much of the phenotypic (gene activity) distinctions between humans.
It may also be much easier to manipulate the expression of existing genes rather than inserting or altering individual genes. Fodder for future manipulation of the human as we come to understand what makes a genius.