Scientists have long sought better tools to study teeth and bones from ancient humans. In the past, they’ve had to scour many ancient remains to find a sample preserved well enough to analyze.
Now cheaper techniques and new methods that make damaged DNA legible to commercial sequencers are powering a boom in ancient DNA analysis.
Today, scientists can even analyze microscopic traces of DNA found in dirt Neanderthals urinated in—no teeth or bones required. In November, the field now known as paleogenetics took center stage when Svante Pääbo, a geneticist at the Max Planck Institute for Evolutionary Anthropology, won a Nobel Prize for his foundational work.
Ancient DNA analysis has led to the discovery of two extinct species of human—Homo luzonensis and Denisovans—and taught us that modern humans carry a substantial amount of Denisovan and Neanderthal DNA. And the number of ancient human individuals for whom we now have whole-genome data has jumped drastically, from just five in 2010 to 5,550 in 2020.
By indicating that India’s population came from a mix of ancestors, these techniques have undermined the caste system. DNA from a 2,500-year-old battlefield in Sicily has revealed that ancient Greek armies were more diverse than historians depicted.
Old samples can unravel modern health mysteries, too. Last year scientists identified a single mutation that made people 40% likelier to survive the Black Death—and it’s also a risk factor for autoimmune issues like Crohn’s disease.
Differences in how cultures believe human remains should be treated will keep creating ethical and logistical questions for scholars seeking to work with ancient DNA. But its revelations are already rewriting history.