Using miniature brains grown in Petri dishes we begin to understand what separates us from chimpanzees and macaques
That we have a brain different from that of chimpanzees is, in principle, something quite known. And yet, we share 99% of our genome with them. That makes it inevitable to wonder about the things that change during the development of our brains to generate such different things.
Subject that, being completely honest, we did not finish understanding very well. Now a team coordinated by Sabina Kanton, Michael James Boyle and Zhisong He have used laboratory-grown brain organoids to explore in detail what dynamics in gene expression and regulation are different between great apes and humans.
A chimpanzee brain in a petri dish
The first surprise is that many of the processes are very similar, but with substantial differences. "We observed more pronounced cortical neuron maturation in chimpanzee and macaque organoids compared to human organoids at the same point of development. This would suggest that human neuronal development takes place more slowly than in the other two primates," explained Barbara Treutlein, a member of the research team.
But on the other hand, what the researchers found is that, even in areas as characteristically human as the adult prefrontal cortex (a region that influences complex cognitive behaviors), the fundamental differences have to do with how it expresses itself. the DNA that (in many cases) we share. This places us in a more subtle and interesting dimension of neuronal evolution.
"Our data provides a resource to guide further research on the mechanisms of gene regulatory dynamics during early brain development, especially those that potentially distinguish developing human and chimpanzee brains," the authors conclude. And it really is a very interesting map that gives us clues about who we really are. Much remains to be investigated, but it is comforting to see the branches of the great tree of evolution begin to clear.