Europe was covered in thick ice sheets around the time of the last glacial maximum around 20,000 years ago, during which time sea levels were more than a hundred metres lower than today.
Shielding themselves from the frigid conditions in western Europe, cave-dwelling humans occupied rock shelters and caverns and in one site near Granada in Spain, archaeologists have unearthed remains providing the oldest human genome recorded in the region.
This 23,000-year-old genome from Cueva del Malalmuerzo is the oldest found in the Andalusian region and one of the oldest recorded. Researchers from the Max Planck Institute for Evolutionary Anthropology have connected these genetic remains to those of a 35,000-year-old Belgian specimen found in 2016.
However despite being separated by a dozen kilometres from North Africa across the Strait of Gibraltar, researchers found there was no connection to lineages found in modern-day Morocco.
While fragments of genetic material are often retrieved from human remains, a genome is the complete set of an organism’s DNA, a bit like finding a box of building blocks with instructions, rather than loose plastic bricks.
Genetic material requires very specific conditions to be preserved for such long time periods. Hot and dry conditions like those experienced on the surface of regions in south Spain and northern Africa are not ideal, but caves are a different story.
Fortunately with these digs, the DNA was intact and has enabled the tracing of the specimen to a specific group of humans that settled the Iberian Peninsula at the end of the last Ice Age.
“With Malalmuerzo, we managed to find the right place and the right time period to trace a Palaeolithic human group back to one of the proposed Ice Age refugia,” says researcher Wolfgang Haak.
“It is remarkable to find such a long-lasting genetic legacy on the Iberian Peninsula, especially since this pre-Ice Age ancestry had long since disappeared in other parts of Europe.”
The oldest known genome originates from a female skull found in Czechia, identified from a 45,000 year old skull.