For decades many scientists thought human DNA had hardly changed over the last 50,000 years, believing civilization had halted natural selection. Professor David Reich of genetics and human evolutionary biology said this view assumed an evolutionary optimum had been reached long ago.

Using the largest collection of ancient human DNA ever assembled—samples from 5,836 ancient humans gathered with help from about 250 archaeologists—Reich and first author Ali Akbari built a Genetic Relationship Matrix to filter out migration noise. New statistical methods let them detect subtle shifts in gene frequency across 16,000 individuals spanning 18,000 years in modern‑day Europe.

The analysis revealed 479 genes showing evidence of natural selection, with immunity‑related genes most affected. For example, a multiple‑sclerosis‑linked variant rose to 16 % of the population 4,000 years after appearing 6,000 years ago, then receded. A tuberculosis‑risk gene followed a similar arc, and selection intensity has accelerated in the past 5,000 years compared with the preceding 5,000 years.

Reich cautions that gene functions may have changed over time, so today’s health or intelligence cannot be inferred from these variants. The team plans to add data from isolated populations and explore the identified genes’ ancient roles, concluding that humanity is far from done evolving as culture, economy, and environment continue to drive rapid change.