Researchers have analyzed the DNA from 7,000-year-old bones of two cavemen unearthed in Spain, and have managed to sequence fragments of their genomes, making them the oldest modern human specimens ever found thus far. Ironically, the researchers found that the cavemen bear little genetic resemblance to people living in the region today, instead sharing ancestry with current populations of northern Europe.
The skeletons of two young adult males were discovered by chance in 2006 by cave explorers in a cavern high in the Cantabrian mountain range, northern Spain, at an altitude of about 1,500 meters. This made the region particularly cold, especially during that period of time, but which ultimately helped preserve the DNA in the bones. Judging by the ornament that one was found with of red-deer canines embroidered onto a cloth, also remarkably preserved, the cavemen were hunter-gatherers of the Mesolithic period, before agriculture spread to the Iberian Peninsula with Neolithic settlers from the Middle East.
"These are the oldest partial genomes from modern human prehistory," said researcher Carles Lalueza-Fox, a paleogeneticist at the Spanish National Research Council.
The team of scientists were able to rescue the complete mitochondrial DNA, the genetic information housed in sub-cellular structures called mitochondria, from "Braña1," one of the two skeletons.
"Despite their geographical distance, individuals from the regions corresponding to the current England, Germany, Lithuania, Poland and Spain shared the same mitochondrial lineage," said Lalueza-Fox in a statement. "These hunters-gatherers shared nomadic habits and had a common origin.
Previously, researchers have managed to sequence the complete genomes of our closest extinct relatives, the Neanderthals and the Denisovans. For the present study, the scientists recovered 1.34 percent and 0.5 percent, respectively, of the human genomes from the bones of these two cave men.
"There are many works that claim the Basques [of the Iberian Peninsula] could be descendants from Mesolithics that became isolated in the Basque country," Lalueza-Fox said. "We found the modern Basques are genetically not related to these two individuals."
The researchers now aim to complete the genomes of both cavemen. Such data could help "explore genes that have been modified with the arrival of the Neolithic in the European populations," Lalueza-Fox said.