Groundbreaking new DNA extraction techniques allowed researchers to identify the world's oldest-known DNA.
The German team was able to determine a 400,000-year-old member of the Homo genus from a cave site in Spain, a Max-Planck-Gesellschaft news release reported. The ancient hominines were dubbed Homo heidelbergensis.
They found the ancient hominine's DNA was related to the mitochondrial genome of Denisovans, a relative of Asian Neanderthals.
The site, called Sima de los Huesos (the Bone Pit), contains the world's largest collection Middle Pleistocene hominine fossils. Twenty-eight skeletons have been excavated from the site over the past 20 years.
The team tested their new DNA-detecting strategy on a cave bear found at the site. The researchers then sampled powder from a heidelbergensis thigh bone. The team then sequenced the genome of the mitochondria (mtDNA).
"Our results show that we can now study DNA from human ancestors that are hundreds of thousands of years old. This opens prospects to study the genes of the ancestors of "Neanderthals" and Denisovans. It is tremendously exciting" says Svante Pääbo, director at the Max Planck Institute for Evolutionary Anthropology. The team compared their findings with genes in "Neandertals, Denisovans, present-day humans, and apes."
To the researcher's surprise, they found the hominine was related to Denisovans.
"The fact that the mtDNA of the Sima de los Huesos hominin shares a common ancestor with Denisovan rather than [Neanderthal] mtDNAs is unexpected since its skeletal remains carry [Neanderthal]-derived features," Matthias Meyer, study leader from the Max Planck Institute for Evolutionary Anthropology, said.
The researchers believed the Sima de los Huesos hominines were either related to both Neanderthals and Denisovans, or there was gene flow from yet another hominine group.
"This unexpected result points to a complex pattern of evolution in the origin of [Neanderthals] and modern humans. I hope that more research will help clarify the genetic relationships of the [hominines] from Sima de los Huesos to [Neanderthals] and Denisovans" Juan-Luis Arsuaga, director of the Center for Research on Human Evolution and Behavior, said.