BRENT: One study described a gene that not only triggers brain growth, it can stimulate creation of the folds and fissures on the brain surface that are characteristic of primate brains and exceptionally prominent in the human brain. Folding increases the brain’s surface area, making more room for neurons to process and store information.
Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, went looking for a gene that was particularly active during development of the cortex, which happens very early in life.
The cortex is the thin outer layer of brain tissue believed to be essential for memory, attention, awareness, and, in humans, thought, language, and consciousness. They found the gene by examining gene activity in aborted human fetal tissue and comparing it with tissue from mouse embryos, identifying 56 human genes that the mouse lacked.
The most active was a gene called ARHGAP11B, a partial duplication of an existing gene. The duplication arose sometime after human evolution split off from the line that led to chimps some 5 or 6 million years ago. It is uniquely human, being present in Neanderthals and Denisovans, our long-gone kin, as well as anatomically modern humans, the last Homo standing.
