DNA evidence has revealed that early European farmers spend thousands of years eating dairy that most likely made them sick.
New research by international scientists has revealed that ancient Europeans adapted the ability to digest dairy much later than expected.
It's long been known that after humans transitioned from hunter gatherers to farmers, many populations also evolved the ability to tolerate lactose, a sugar found in dairy.
But new DNA evidence now shows that this ability evolved much later in certain populations - and for 4,000 years ancient Europeans were eating cheese, despite not being able to stomach it.
The study, which has been published in Nature Communications, analysed DNA taken from the remains of 13 human skulls dating from 5,700 BC to 800 BC.
The results show that cultural shifts thoughout human history can also be linked to genetic changes.
"The genomes do seem to shift as new technologies come about," Daniel Bradley, a co-author of the study from Trinity College Dublin in Ireland, told Rachel Feltman from the Washington Post. "You can't look at this and think that farming and metallurgy are technologies that come into the culture by osmosis. They come with people. Genomes and technology migrate together."
However, in the past, scientists had estimated that lactose tolerance must have evolved around 7,000 years ago or more, when cheese-making first started. But the researchers found that the genes didn't actually appear until 3,000 years ago.
While the sample size was quite small, the methods used by the scientists allowed them to extract far more DNA information than usual from the remains. As Feltman explains in the Washington Post:
"By using the densest bone in the human body (one found in the inner ear) they were able to recover from 40 to 87 percent of each individual's genetic information - compared to the 1 percent that most bone samples yield."
The next step is to map the distribution of the lactose-tolerant gene further, and find out more about how our genetics changed in response to our diet.
Source: Washington Post