Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Xiangchun Ju
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Luise Fast
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Sebastian Ebert
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Anne Weigert
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Sabina Kanton
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Theresa Schaffer
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
Nael Nadif Kasri
Department of Human Genetics and Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behavior, Radboudumc, Nijmegen, Netherlands
Barbara Treutlein
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
We generated induced excitatory neurons (iNeurons, iNs) from chimpanzee, bonobo, and human stem cells by expressing the transcription factor neurogenin-2 (NGN2). Single-cell RNA sequencing showed that genes involved in dendrite and synapse development are expressed earlier during iNs maturation in the chimpanzee and bonobo than the human cells. In accordance, during the first 2 weeks of differentiation, chimpanzee and bonobo iNs showed repetitive action potentials and more spontaneous excitatory activity than human iNs, and extended neurites of higher total length. However, the axons of human iNs were slightly longer at 5 weeks of differentiation. The timing of the establishment of neuronal polarity did not differ between the species. Chimpanzee, bonobo, and human neurites eventually reached the same level of structural complexity. Thus, human iNs develop slower than chimpanzee and bonobo iNs, and this difference in timing likely depends on functions downstream of NGN2.
