Researchers have uncovered a new clue about human origins after discovering the oldest known human DNA in a legendary Spanish archeological site called Sima de los Huesos, or the "Pit of Bones."
Researchers were able to extract DNA from a leg bone that was estimated to be 400,000 years old. After extracting the DNA from a femur bone, Matthias Meyer, who published his findings in a study in the journal Nature, was able to replicate the entire genome for the ancient human relative.
The genetic sequence surprised researchers, who thought it was likely that the sequence would reveal that remains were related to the Neanderthals. Instead, the genetic sequence revealed that this early human species is related to another genetic cousin of modern humans,the mysterious Denisovans.
Little is known about the Denisovans, who are thought to have been common throughout the regions now known as Asia and Eastern Europe. This early human species was discovered after genetic sequencing was used to map DNA through the ancient pinkie bone of a girl in 2010.
Anthropologists and genetic experts said the findings from the Pit of Bones could help shed light on how early human species evolved and spread across different continents.
"This places what we have to assume from the genetic sequence is an earlier branch of our family that goes back even further" in time, said Kenneth Kidd, professor of genetics at the Yale University School of Medicine. Kidd said since the DNA was from 400,000 years ago, this mysterious human relative likely predated most Neanderthals.
Kidd explained that one reason there is little known about the Denisovans is that "the Neanderthals may have annihilated the Denisovans," similar to how the Neanderthals died off as modern humans became more populous.
If you're wondering if you're related to the ancient DNA, Kidd said there is no evidence that the Denisovans provided any genetic material for the modern human race.
Theodore Schurr, professor of anthropology at the University of Pennsylvania, said the findings were significant since it showed clearly how DNA mapping was changing the field of anthropology. Schurr said solely from the skeletal remains researchers thought the human species appeared to be related to Neanderthals.
"This is also significant because it's the DNA coming from the oldest remains," said Schurr. "It's interesting to compare the skeletons to the genetics because the stories may not match up."