A gene found only in humans and active in the cerebral cortex can enlarge the ferret brain
Medical Xpress | January 08, 2019
The human brain owes its characteristic wrinkled appearance to its outer layer, the cerebral cortex. During human evolution, the neocortex, the evolutionarily youngest part of the cerebral cortex, expanded dramatically and had to fold into wrinkles to fit inside the restricted space of the skull. The human neocortex supports advanced cognitive skills such as reasoning and language. But how did the human neocortex become so big? The answer may lie in genes that are unique to humans, such as ARHGAP11B.
Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden found that this human-specific gene, when introduced into the developing brain of ferrets, can cause an enlargement of their neocortex. ARHGAP11B causes neural progenitor cells, which are cells that produce neurons, to make more of themselves for a longer period of time. The result is an expanded neocortex. The human neocortex is roughly three times bigger than that of our closest relatives, the chimpanzees, and is the seat of many of the higher cognitive functions that are unique to humans, such as our speech or the ability to learn. A key question for scientists is how in human evolution the neocortex became so big.