In 2010, researchers published the first genome sequence from an ancient human, using tufts of hair from a man who lived around 4,000 years ago in Greenland. In the 13 years since, scientists have generated genome data from more than 10,000 ancient people — and there’s no sign of a slowdown.
“I feel truly gobsmacked that we have gotten to this point,” says David Reich, a population geneticist at Harvard Medical School in Boston, Massachusetts. His team maintains a database of published ancient-human genome data, called the Allen Ancient DNA Resource, which was described this month in a preprint study on bioRxiv.
Before 2010, ancient-DNA studies focused on limited stretches of DNA, such as the roughly 16,500-base-pair-long mitochondrial genome or short segments of the nearly 3.1 billion base pairs in the human genome. Since then, advances in DNA sequencing have made it feasible to decode entire ancient genomes. Initially, this process was labour-intensive, and relied on finding rare samples with high levels of genuine ancient DNA. As a result, it took several years to generate genome data from a dozen individuals.
Each year since 2018, researchers have produced genome data from thousands of ancient humans, thanks to technological advances in DNA sequencing and extraction methods. For many samples — including those from Reich’s lab — researchers sequence a set of one million DNA bases that tend to vary between people, instead of an entire genome, which is much costlier.
The field’s exponential growth has also been propelled by a focus on more recent samples from the 12,000 years since the last ice age ended, which are more abundant and tend to have higher-quality DNA than older human remains. [Continue reading…]