Overview
- Published in Science, the University of Pennsylvania–led study infers predominantly male Neanderthal–female modern human pairings.
- Comparisons show Neanderthal X chromosomes carry an excess of modern human DNA, while the modern human X retains little Neanderthal DNA.
- Demographic modeling reproduces the observed asymmetry under strong directional mating, challenging “toxic X” selection‑only explanations.
- External experts commend the approach yet warn about possible statistical artifacts and note the lack of archaeological evidence for specific behaviors.
- Analyses of three Neanderthal genomes indicate roughly 62% more modern human DNA on their X chromosomes than on other chromosomes.