Science
No Fixed Genetic Differences Found Between Humans 50,000 Years Ago and Today
Dwarkesh Patel Podcast
David Reich – Why the Bronze Age was an inflection point in human evolution
What was said
"We looked really hard, and right across all the DNA we could look at, we couldn't find anything more than 4 or 500— more recent than 4 or 500,000 years ago. This is like a crazy result because, uh, it looks like there's no key selective sweeps that have occurred in this period that is ancestral to everyone living today."
A 2016 study by Reich's group found no genetic positions where all modern humans share a common ancestor more recently than 400,000-500,000 years ago, indicating no single mutation swept to fixation during the cognitive revolution 50,000-100,000 years ago. This suggests behavioral modernity emerged through polygenic adaptation—many small genetic shifts—or was primarily cultural rather than genetic. The finding challenges theories requiring specific genetic changes to explain modern human behavior.
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- Programme
- Dwarkesh Patel Podcast
- Episode
- David Reich – Why the Bronze Age was an inflection point in human evolution
- Clip time
- 1:05:06
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Dwarkesh Patel Podcast