Human TKTL1 implies greater neurogenesis in frontal neocortex of modern humans than Neanderthals.

Neanderthal brains were similar in size to those of modern humans. We sought to investigate potential differences in neurogenesis during neocortex development. Modern human transketolase-like 1 (TKTL1) differs from Neanderthal TKTL1 by a lysine-to-arginine amino acid substitution.

Longer metaphase and fewer chromosome segregation errors in modern human than Neanderthal brain development.

Since the ancestors of modern humans separated from those of Neanderthals, around 100 amino acid substitutions spread to essentially all modern humans. The biological significance of these changes is largely unknown. Here, we examine all six such amino acid substitutions in three proteins known to have key roles in kinetochore function and chromosome segregation and to be highly expressed in the stem cells of the developing neocortex.

Human-specific gene ARHGAP11B promotes basal progenitor amplification and neocortex expansion.

Evolutionary expansion of the human neocortex reflects increased amplification of basal progenitors in the subventricular zone, producing more neurons during fetal corticogenesis. In this work, we analyze the transcriptomes of distinct progenitor subpopulations isolated by a cell polarity-based approach from developing mouse and human neocortex. We identify 56 genes preferentially expressed in human apical and basal radial glia that lack mouse orthologs.

Basolateral rather than apical primary cilia on neuroepithelial cells committed to delamination.

Delamination of neural progenitors from the apical adherens junction belt of the neuroepithelium is a hallmark of cerebral cortex development and evolution. Specific cell biological processes preceding this delamination are largely unknown. Here, we identify a novel, pre-delamination state of neuroepithelial cells in mouse embryonic neocortex.