David Reich – Bronze Age shock, the Neanderthal puzzle, & the sudden spread of farming

Summary

Dwarkesh Patel interviews Harvard ancient DNA professor David Reich about a new preprint showing natural selection has been widespread and accelerating over the last 10,000 years, especially in the Bronze Age, with strong effects on immune, metabolic, and cognitive traits. They discuss why selection signals were previously missed, what this implies about farming, intelligence, body fat, and disease. The conversation ends with Reich's speculative whiteboard model that Neanderthals may be culturally modern humans genetically swamped by archaic populations.

• Ancient DNA sample sizes finally allow direct measurement of selection-driven allele frequency changes.
• The study finds natural selection pervasive despite being only about 2% of total frequency change.
• Selected traits are enriched for immune and metabolic functions, with Bronze Age intensification.
• Genetic predictors of cognitive performance rose about one standard deviation over 10,000 years, mostly 4,000–2,000 years ago.
• Reich proposes a new model in which a Middle Stone Age population expanded into Europe and Africa, producing Neanderthals via genetic swamping.
• No direct public market or tradable investment conclusions are presented.