Insights into the development of the human brain and differences in this process compared to other great apes are presented in a study in Nature this week. The study reveals features of brain development that are unique to humans, and outlines how these processes have diverged from those in other primates.
Since humans diverged from chimpanzees and the other great apes, the human brain has changed dramatically. However, the genetic and developmental processes responsible for this divergence are not fully understood. Cerebral organoids (brain-like tissues), grown from induced pluripotent stem cells, offer the possibility to study the evolution of brain development in the laboratory.
Barbara Treutlein and colleagues analysed human stem cell-derived cerebral organoids for four months through the course of development from pluripotent cells to explore gene-regulatory changes that are specific to humans. The authors then examined chimpanzee and macaque cerebral organoids to understand how organoid development differs in humans. They observed more pronounced cortical neuron specification 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.
The authors conclude that their data provide a resource to guide further research into the mechanisms of gene regulation that distinguish developing human and chimpanzee brains.
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