Amazing stuff!
"More than 500,000 years ago, the ancestors of Neanderthals and modern humans were migrating around the world when a fateful genetic mutation caused some of their brains to suddenly improve. This mutation ... dramatically increased the number of brain cells in the hominins that preceded modern humans, probably giving them a cognitive advantage over their Neanderthal cousins. ..."
"... Pinson et al. report that expression of a variant of human transketolase-like protein 1 (TKTL1) increases the number of bRGs in modern humans and thereby the output of upper layer projection neurons. This genetic change could contribute to differences in cognition with extinct archaic humans."
From the abstract:
"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. Using overexpression in developing mouse and ferret neocortex, knockout in fetal human neocortical tissue, and genome-edited cerebral organoids, we found that the modern human variant, hTKTL1, but not the Neanderthal variant, increases the abundance of basal radial glia (bRG) but not that of intermediate progenitors (bIPs). bRG generate more neocortical neurons than bIPs. The hTKTL1 effect requires the pentose phosphate pathway and fatty acid synthesis. Inhibition of these metabolic pathways reduces bRG abundance in fetal human neocortical tissue. Our data suggest that neocortical neurogenesis in modern humans differs from that in Neanderthals."
Human TKTL1 implies greater neurogenesis in frontal neocortex of modern humans than Neanderthals (no public access)
Scaling brain neurogenesis across evolution (no public access) A genetic change could explain increased cortical neurogenesis in modern humans
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