The Indigenous peoples of the Bolivian highlands are survivors. For thousands of years they have lived at altitudes of more than two miles, where oxygen is about 35 percent lower than at sea level.

A massive study of ancient DNA from nearly 16,000 people across more than 10,000 years in West Eurasia reveals that natural selection has shaped modern human genomes far more than previously thought.

When most people think about natural selection, they imagine individuals competing with one another: The fastest animal escapes predators, the strongest plant produces more seeds, and the most ...