With respect to the folding of brain matter:
These genetic differences are also correlated with changes in grey matter neurons, with the study finding variations in the number of arms – or dendrites – that neurons grow in these regions during the folding process.
“We believe the regions that fold outward and inward are programmed to behave differently, and the shape of the neurons affects the way these areas fold,” Quezada Rojas says. “
Understanding how brains fold and misfold” at Cosmos
The paper will be available here.
It’s almost like there are laws of what will work in biology; it’s not all just random after all.