Recent human selection is not quiescent

One-line summary: Podcast / speaker claim — david-reich and ali-akbari say ancient-DNA frequency trajectories show natural selection still moving many sites over the last ~10,000 years, against a mainstream “selection went quiet” story. Not a paper citation.

The insight

Reich’s podcast claim is methodological first: a single genome is rich for relatedness / history, but frequency change at a trait-affecting site needs large sample sizes. He says those sizes only recently existed, and that the resulting scan finds selection “vibrating” across the genome rather than sitting still.

Treat every number and enrichment below as what the speakers said on this podcast, not as vault-verified GWAS or preprint results.

Evidence

• david-reich in 2026-05-08-podcast-dwarkesh-podcast-david-reich-why-the-bronze-age-was-an: "when you are interested in how a particular genetic variant that Affects something like your skin pigmentation, or affects your ability to digest cow's milk into adulthood, or affects a behavioral trait. When you want to see how that changes over time. A single person gives you only one sample or maybe two samples... To get a high resolution picture of how the frequency changes over time, you need to have very big sample sizes"
• david-reich in 2026-05-08-podcast-dwarkesh-podcast-david-reich-why-the-bronze-age-was-an: "the mainstream view in human evolution in the last several decades has been that natural selection has been pretty quiescent over the last several hundred thousands of years of human history."
• david-reich in 2026-05-08-podcast-dwarkesh-podcast-david-reich-why-the-bronze-age-was-an: "multiple analyses, we do suggest that the genome is vibrating with natural selection... instead of being quiescent. Natural selection is everywhere. Even though it's only 2% of the frequency change, it's tugging the positions in one direction or the other everywhere."
• david-reich in 2026-05-08-podcast-dwarkesh-podcast-david-reich-why-the-bronze-age-was-an: "there was a vast enrichment by about a four or five fold for immune traits... we saw a strong enrichment for metabolic traits... and really almost no detectable enrichment as far as we could tell, for behavioral traits or for psychiatric traits."
• david-reich in 2026-05-08-podcast-dwarkesh-podcast-david-reich-why-the-bronze-age-was-an: "it might seem... that there's been no selection for behavior... But in fact that's a wrong conclusion... behavioral traits... are underpinned by much larger numbers of genes of weak effect. And we just don't have the statistical power to detect these very weak signals there."

Why it matters to science

This is the first biology / ancient-genomics claim-set in the science thread. It is a method + result chip from a long-form interview, not a filed paper.

Why it matters to history

Reich also says the field already succeeded at migration / mixture / sex-bias history from ancient DNA, and that frequency work is the biology layer on top of that history. Do not collapse this into late-bronze-age-collapse — that page is about Eastern Mediterranean systems collapse c. 1200–1150 BCE.

Contradictions / tensions

• Show notes claim a ~1 SD rise in a “genetic predictor of cognitive performance” over 10,000 years. In the transcript Reich separates migration jumps in that predictor from selection on top of them, and warns that “years of schooling” predictors correlate with many other traits. Do not promote the show-notes sentence as a wiki fact.
• Speaker 4 / Speaker 5 are heuristic-fallback labels (ad read). Not attributed.

Open questions

• Where is the preprint, and which numbers survive peer review?
• How much of the “2% of frequency change is selection” figure is method-dependent?

Related

• bronze-age-selection-pulse
• neanderthals-as-swamped-modern-humans
• david-reich
• ali-akbari
• late-bronze-age-collapse — different subject (collapse event, not this selection scan)