The agricultural revolution was one of the most profound events in human history, leading to the rise of modern civilization. Now, in the first study of its kind, an international team of scientists has found that after agriculture arrived in Europe 8,500 years ago, people’s DNA underwent widespread changes, altering their height, digestion, immune system and skin color.

Researchers had found indirect clues of some of these alterations by studying the genomes of living Europeans. But the new study, they said, makes it possible to see the changes as they occurred over thousands of years.

“For decades we’ve been trying to figure out what happened in the past,” said Rasmus Nielsen, a geneticist at the University of California, Berkeley, who was not involved in the new study. “And now we have a time machine.”

Before the advent of studies of ancient DNA, scientists had relied mainly on bones and other physical remains to understand European history. The earliest bones of modern humans in Europe date to about 45,000 years ago, researchers have found.