Genetic tweaks built humans’ bigger brains
Experiments in mice show how to grow a wrinkled cortex
![Big Brain](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/02/ta_bigbrain_feat_free.jpg?fit=860%2C460&ssl=1)
FOLD IT A gene that only humans have can make the normally smooth outer layer of mouse brains develop folds similar to those in human brains (upper right center). The gene may have been important for the evolution of big human brains.
M. Florio and W. Huttner/Max Planck Institute of Molecular Cell Biology and Genetics