Oldest human DNA helps pinpoint when early humans interbred with Neanderthals

Human DNA recovered from remains found in Europe is revealing our species' shared history with Neanderthals. The trove is the oldest Homo sapiens DNA ever documented, scientists say.

Scientists say they have recovered the oldest known Homo sapiens DNA from human remains found in Europe, and the information is helping to reveal our species’ shared history with Neanderthals.

The ancient genomes sequenced from 13 bone fragments unearthed in a cave beneath a medieval castle in Ranis, Germany, belonged to six individuals, including a mother, daughter and distant cousins who lived in the region around 45,000 years ago, according to the study that published Thursday in the journal Nature.

The genomes carried evidence of Neanderthal ancestry. Researchers determined that the ancestors of those early humans who lived in Ranis and the surrounding area likely encountered and made babies with Neanderthals about 80 generations earlier, or 1,500 years earlier, although that interaction did not necessarily happen in the same place.

Scientists have known since the first Neanderthal genome was sequenced in 2010 that early humans interbred with Neanderthals, a bombshell revelation that bequeathed a genetic legacy still traceable in humans today.

However, exactly when, how often and where this critical and mysterious juncture in human history took place has been hard to pin down. Scientists have believed interspecies relations would have occurred somewhere in the Middle East as a wave of Homo sapiens left Africa and bumped into Neanderthals, who had lived across Eurasia for 250,000 years.

A broader study on Neanderthal ancestry, published Thursday in the journal Science, that analyzed information from the genomes of 59 ancient humans and those of 275 living humans corroborated the more precise timeline, finding that the majority of Neanderthal ancestry in modern humans can be attributed to a “single, shared extended period of gene flow.”

“We were far more similar than we were different,” Priya Moorjani, a senior author of the Science study and an assistant professor in the department of molecular and cell biology at the University of California, Berkeley, said at a news briefing.