A recent study conducted by an international team of scientists reported that agriculture's arrival in Europe 8,500 years ago altered human DNA. Specifically, Earth's populace saw changes to its height, digestion, immune system, and skin color. The study, the first of its kind, considered differences between genetics from living Europeans and their ancestors. This allowed researchers to see genetic changes that occurred over thousands of years.
Researchers including Dr. David Reich of Harvard Medical School found that the earliest bones of modern Europeans were from 45,000 years ago. Early Europeans lived as hunter-gatherers for about 35,000 years. 8,500 years ago, the first farmers left their mark on the archaeological record of Europe when they started growing their own crops. Instead of hunting animals, Europeans began to adapt to an agrarian society.
One of the specific genetic changes this study showed was in a gene our ancestors had, called SLC22A4, that we no longer have. This gene helped our ancestors survive with only a low amount of ergothioneine, an important amino acid. At the time they became farmers and began growing crops, wheat had a low amount of ergothioneine and SLC22A4 helped them absorb enough of the nutrient. But, this gene also had a downside: it came with a higher risk of digestive disorders, such as Irritable Bowel Syndrome (IBS).
Rasmus Nielson, a geneticist at the University of California not involved in the study, is excited about its results. He stated, “For decades we have been trying to figure out what happened in the past, and now we have a time machine.”
Most changes between our ancestors DNA and our DNA today are noticeable. It's amazing to see how scientists today are able to make new discoveries when studying DNA that is from so far in the past.
The New York Times