The genetics of humanness

Roughly speaking, modern humans differ from chimpanzees with probability 0.01 at a particular base in the genome, from neanderthals with probability 0.003, and from each other with probability 0.001 (this final number varies by about 15% depending on ancestral population). The neanderthal research is particularly interesting in that we will eventually be able to determine the specific genetic changes that make modern humans different (smarter?) than neanderthals. Certain regions in the genome, known as HARs (Human Accelerated Regions) are conserved in mammals such as mice, dogs, chimpanzees, even neanderthals, but show rapid recent changes in humans. It's reasonable to suspect that these regions are doing interesting things ...

See also this recent paper: Analysis of Human Accelerated DNA Regions Using Archaic Hominin Genomes (PLoS).