RT Journal
A1 Liu, Xiling
A1 Somel, Mehmet
A1 Tang, Lin
A1 Yan, Zheng
A1 Jiang, Xi
A1 Guo, Song
A1 Yuan, Yuan
A1 He, Liu
A1 Oleksiak, Anna
A1 Zhang, Yan
A1 Li, Na
A1 Hu, Yuhui
A1 Chen, Wei
A1 Qiu, Zilong
A1 Pääbo, Svante
A1 Khaitovich, Philipp
T1 Extension of cortical synaptic development distinguishes humans from chimpanzees and macaques
JF Genome Research 
JO Genome Research 
YR 2012 
FD February 02 
DO 10.1101/gr.127324.111 
UL http://genome.cshlp.org/content/early/2012/01/30/gr.127324.111.abstract 
AB Over the course of ontogenesis, the human brain and human cognitive abilities develop in parallel, resulting in a phenotype strikingly distinct from that of other primates. Here, we used microarrays and RNA-sequencing to examine human-specific gene expression changes taking place during postnatal brain development in the prefrontal cortex and cerebellum of humans, chimpanzees, and rhesus macaques. We show that the most prominent human-specific expression change affects genes associated with synaptic functions and represents an extreme shift in the timing of synaptic development in the prefrontal cortex, but not the cerebellum. Consequently, peak expression of synaptic genes in the prefrontal cortex is shifted from <1 yr in chimpanzees and macaques to 5 yr in humans. This result was supported by protein expression profiles of synaptic density markers and by direct observation of synaptic density by electron microscopy. Mechanistically, the human-specific change in timing of synaptic development involves the MEF2A-mediated activity-dependent regulatory pathway. Evolutionarily, this change may have taken place after the split of the human and the Neanderthal lineages.