Mini-Brains Show Why Human Brains Grow Larger Than Those of Other Apes
The ZEB2 gene controls cell shape and motility. “Essentially, when this gene is switched on, the cells are less ‘sticky’ and can leave and go elsewhere,” says Madeline Lancaster. By delaying the gene’s activation, early human brain cells are able to stick together and multiply for longer before specializing into mature nerve cells, she says. To make sure ZEB2 was responsible, the team switched the gene on earlier in the human organoids and later in the gorilla organoids. “The [human] brain organoids started to look like the ape cells and, vice versa, the gorilla cells actually ended up looking like the human cells,” says Lancaster.