Richard Klein has long claimed that the archeological record shows an abrupt increase in sophistication about 50,000 years. Before 50,000 years ago Sapiens behaved more or less like Neanderthals and were largely confined to the continent of Africa with few complex tools and zero representational art. After 50,000 years ago, we suddenly colonized every continent except Antarctica, killed off all the Megafauna living outside Africa, drove all other human species to extinction, and filled our camp grounds with stunning works of art. Klein believed that such a massive rapid change could only be explained by a brain mutation making us smarter.

I on the other hand have argued Klein had it backwards. Getting smarter didn’t cause us to leave Africa. Leaving Africa (and facing the cold) selected for higher IQ.

However new research may clarify this issue once and for all. Scientists have discovered a major mutation in Sapiens that may have made us smarter than Neanderthals. Of the 19,000 genes in the human genome, only 96 protein encoding mutations separate us from Neanderthals. One of these alters the TKTL1 gene which affects the brain’s cortex, especially the frontal lobe.

Proving this mutation played a causal role in brain growth, Dr. Anneline Pinson and her team injected the Sapien version in animals as different from us as mice and ferrets and watched in awe as it caused their brains to grow more neurons. Next, with consent from the mothers, they looked at human fetal brain tissue from aborted babies and after snipping out the TKTL1 gene from the cells using molecular scissors, the number of progenitor cells giving rise to neurons declined.

Lastly, they edited Sapien embryonic stem cells to either have have the Sapien specific mutation or the ancestral version carried by Neanderthals and apes, put them in a chemical bath and coaxed them into becoming a blob of brain tissue called brain organoids or mini brains, and found the Sapien version produced more neurons and scientists suspect, this may explain why our brains are spherical and Neanderthal brains are elongated.

The next questions I have are, exactly when did this mutation occur and how many IQ points is it worth. In the early 2000s there was much excitement in the HBD community about microcephalin mutations supposedly causing major differences in IQ. Now that’s all gone. Too often genetic variants are found to have trivial effects.

However neuroscientist Laurent Nguyen thinks this might be a big deal, recently telling the New York Times “This is really a tour de force. It’s remarkable that such a small change has such a dramatic effect on the production of neurons.”

Of course ethical standards prohibit scientists from editing the embryos of actual future children just to see how it affects their IQ, though perhaps some government might do this in secret.

But with nearly eight billion people on the planet, and only 6 billion nucleotides in the human genome, odds are there might be someone out there who by chance, has the Neanderthal version of the TKTL1 gene. That person needs to take a brain scan and an IQ test.