If newcomers in your region had a great idea, wouldn’t you adopt it? Or what the heck, wouldn’t you use trading opportunities to make googly eyes at someone?
Roughly 7,500 years ago early Europeans were hunter-gatherers. At some point, however, agriculture, which had begun in the Middle East, was brought in. How did it spread? Did the hunter-gatherers, who included seal-hunting Scandinavians and freshwater fish-eating central Europeans, just say, what a swell idea, and settle down to grow grains?
(In somewhat related news, scientists have found that hunter-gatherers 7,000 years ago had dense bones that had 20 percent more bone mass than farmers from 1,000 years ago. The reason: farming wasn’t nearly as active a life as foraging. Things are getting even worse for us today. As one of the study’s authors said, “There’s seven million years of hominid evolution geared towards action and physical activity for survival, but it’s only in the last say 50 to 100 years that we’ve been so sedentary – dangerously so.”)
An article in Science News, “Written in Bone” by Tina Hesman Saey, describes how DNA studies of skeletons have revealed that in many cases the farmers and the hunter-gatherers existed side by side without interbreeding. Each group had separate DNA markers that did not show up in the other group’s skeletons during the period when both inhabited the same area. In some cases, they had lived side by side for 2,000 years.
This wasn’t 100 percent true, though. In what is now Sweden, the seal-hunters who had been in the region did not show any of the DNA markers of farmers who moved into the area, even though they shared the space for 1,000 years. The farmers’ DNA, on the other hand, began to show the DNA markers for the seal hunters, indicating that some of the hunter-gatherers were joining their group.
This is the sort of fascinating detail that makes me interested in science. These studies open the door on the lives of people thousands of years ago who have previously been hidden to us. In neuroscience terms, my brain’s reward center, the nucleus accumbens, is sending dopamine to my frontal cortex, and in this case dopamine is working as the happy neurotransmitter. (The trigger for the whole process is a sense of wonder, but that’s not something I can explain via neuroscience just yet.)
What I also found fascinating in this Science News article was the information that scientists had identified five waves of farmers who had migrated into Europe over thousands of years. And while agricultural communities usually stay in one place for generations, the DNA also showed that early Europeans moved great distances. Otzi, the name given a 5,300 year old mummy found frozen in the Austrian-Italian Alps in 1991 (reconstructed image to the right, photo: Science News) appears to have been a farmer; yet, he wasn’t from that area, but instead seems to have genetic connections with modern-day Sardinians and Corsicans, 500 kilometers to the southwest.
There’s even the case of the Mal’ta boy, a Siberian who lived 24,000 years ago in the area of Lake Baikal. The genetic markers of his people don’t show up in the DNA of southern Europeans, but they do appear in some northern Europeans. How did the Mal’ta people come to travel across the northern regions, but not go southwest towards southern Europe? Was it just the natural human movement away from populated areas – where threats from other groups perhaps force people to migrate – to less densely populated ones?
As usual, this sort of thing leaves me with more questions, which is something I try to teach my students the value of. Maybe it’s those little blasts of dopamine coursing from my nucleus accumbens to my prefrontal cortex, but I think it’s a wonderful way to go through life.