By turning on a single gene in specific neural cells in the embryonic mouse brain, researchers have made more neurons grow in the neocortex — a region that evolved to be much larger in primates than in other mammals.
Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, and his team developed a mouse model in which they could switch on the Pax6 gene in specific neural progenitor cells — where it is expressed in humans but not in mice. They turned on the gene in cells that give rise to neurons of the neocortex, which controls advanced cognitive abilities. The team found that with sustained Pax6 expression, the progenitor cells proliferated more, resulting in more neurons in parts of the neocortex.
Pax6 could have had an important role in the evolution of the larger primate neocortex, the authors suggest.