New DNA analysis has pegged the first integration between Neanderthals and early modern humans at between 50,000 and 60,000 years ago.

According to BBC News, the study published in the journal Nature was based on the genome sequencing of a 45,000-year-old thighbone found in Siberia. The results suggest that early modern humans intermingled with Neanderthals millions of years earlier than previously thought.

Svante Paabo, a professor at the Max Planck Institute in Leipzig, Germany, is part of a multi-institutional team that collaborated on the study.

"The amazing thing is that we have a good genome of a 45,000 year old person who was close to the ancestor of all present-day humans outside Africa," he told BBC News. "Our analysis shows that modern humans had already interbred with Neanderthals then and we can determine when that first happened much more precisely than we could before."

The study's first author, a postdoctoral fellow at Harvard Medical School (HMS) named Qiaomei Fu, began the research in a lab with David Reich, an HMS professor.

"The ancient Siberian was related equally to West European hunter-gatherers, North Asian hunter-gatherers, East Asians, and the indigenous people of the Andaman Islands off South Asia," Fu told the Harvard Gazette. "The fact that this population separated so early indicates that theories of an early split of people who followed a coastal route to Australia, New Guinea, and coastal Asia are not strongly supported by this data."

Paabo told BBC News that the study will call for further analysis before anyone can claim it has re-written the history on the human line. It does at least suggest that the scientific community did not have it correct before.

"We have caught evolution red handed," he said. "We caution that (mutation) rates may have changed over time and may differ between human populations."