(no subject)

[ukhudshanskiy]

Over the past five years ...our understanding of genetics has become much more sophisticated. While there might only be a 1.6 per cent difference in the genome itself, the way it shapes our minds and bodies is radically different. "The key thing for me," says Taylor, "is that when you compare chimps and great apes with humans you notice how much more gene expression there is in humans."

Gene expression is when certain genes damp down or speed up chemical processes. A team from the Max Planck Institute for Evolutionary Anthropology showed that in human brains, there is a five-fold increase in the rate of gene expression. Other research has shown that more than 90 per cent of the genes in human brains have been "up-regulated" – that is, they have higher levels of gene expression. Most of these genes are associated with the speed of transmission of nerve impulses or energy production to fuel the brain. As Taylor says, "Bigger, faster, greedier, longer-living – that's the evolutionary story of the human brain."

Another genetic difference between us and chimps is "copy number variation". This is where a gene becomes copied, inserted into another part of the genome and yet still works. For instance, GLUD2 is a gene that governs an enzyme involved in nerve signalling in the brain. It is common to all the great apes, including humans – but with us, the gene has been copied, which makes the enzyme work faster. The resulting neurological intensity, says Taylor, "is like swapping a Lee-Enfield rifle for a machine gun".