One of the study's major surprises is the relatively large number of genes that have contributed to human brain evolution. ?For a long time, people have debated about the genetic underpinning of human brain evolution,? said Lahn. ?Is it a few mutations in a few genes, a lot of mutations in a few genes, or a lot of mutations in a lot of genes? The answer appears to be a lot of mutations in a lot of genes. We've done a rough calculation that the evolution of the human brain probably involves hundreds if not thousands of mutations in perhaps hundreds or thousands of genes?and even that is a conservative estimate.?
It is nothing short of spectacular that so many mutations in so many genes were acquired during the mere 20-25 million years of time in the evolutionary lineage leading to humans, according to Lahn. This means that selection has worked ?extra-hard? during human evolution to create the powerful brain that exists in humans.
that from the HHMI.