A New Genetic Map of Human Disease for the Past 37,000 Years

Carl Zimmer writes about the results of a new genetic study of humans and the diseases that afflicted us over the past 37,000 years. It’s a really fascinating read — in part because of how scientific results can defy our expectations. For instance, the researchers expected to find the plague when people first started domesticating animals 11,000 years ago. But they didn’t:

But the ancient DNA defied that expectation. The scientists found that plague and a number of other diseases jumped to people from animals thousands of years later, starting about 6,000 years ago. And those microbes did not jump into early farmers.

Instead, the new study points to nomadic tribes in Russia and Asia. Thousands of years after the dawn of agriculture, those nomads started rearing vast herds of cattle and other livestock.

And then:

Those epidemics were so intense that they changed the genetic profile of the nomads. Last year, Dr. Willerslev and his colleagues found that the nomads experienced a spike in mutations that boosted their immune system and that may have helped them resist the diseases they contracted. But their active immune systems may have also attacked their own bodies, producing chronic diseases such as multiple sclerosis.

These diseases might have played a part in Bronze Age history. In previous research, Dr. Willerslev and other scientists have found evidence that nomads expanded from the steppes of Asia into Europe about 4,500 years ago.

The study published on Wednesday suggests that the nomads may have gotten help from their pathogens. European farmers and hunter-gatherers had not evolved resistance to diseases such as plague and may have died off in huge numbers, making it easier for the nomads to move in.

Read the whole thing — it’s interesting throughout.

• archaeology
• Carl Zimmer
• disease
• DNA
• genetics
• science