Anthropologists have long puzzled over how much contact Neanderthals had with modern humans and when this may have occurred.

Now a 40,000-year-old fossilied human jawbone discovered in Romania suggests that humans and Neanderthals continued breeding in Europe, after coming into contact in the Middle East.

DNA testing revealed a genome with between 4.8 and 11.3 per cent Neanderthal DNA.

A 40,000-year-old fossilied human jawbone discovered in Romania suggests that humans and Neanderthals (illustrated) continued breeding in Europe, after mingling in the Middle East

Typically, between one and four per cent of modern humans' genes come from Neanderthals.

Neanderthals - a human sub-species distantly related to, but genetically different from, modern humans, or Homo sapiens - are thought to have moved from Africa to Europe and possibly Asia between 50,000 and 60,000 years ago.

Palaeogenomicist Qiaomei Fu told attendees of the Biology of Genomes’s meeting in New York last week that the DNA test results hint that the human had Neanderthal in his or her family tree stretching back just four to six generations, Phys.org reported.

The human jawbone at the heart of the study was found in a cave in 2002 and has intrigued experts ever since. This one comes from a Neanderthal and is much thicker and stronger than that of a modern human's

HOW MUCH OF US IS NEANDERTHAL? An ancient partial skull has provided the earliest evidence that modern humans lived alongside Neanderthals and could have interbred 55,000 years ago. Recently discovered in Manot Cave in West Galilee, Israel, the bone sheds new light on our ancient relatives living in the area. The find challenged previous theories that the two species potentially met 45,000 years ago somewhere in Europe. Modern Europeans have inherited between one and four percent of their genes from Neanderthals, meaning the two groups mated at some point in the past. A recent study also suggested that many modern diseases are actually caused by DNA that we inherited from this now extinct branch of the human evolutionary tree. These 'legacy' genes have been linked to an increased risk from cancer and diabetes. Some genes we inherited could have also improved our immunity to other diseases. Scientists have found that part of our HLA system, which helps white blood cells to identify and destroy foreign material in the body, could have come from Neanderthals. Advertisement

Last year, her team found a 45,000-year-old human bone fragment in Siberia and have now pinpointed visible Neanderthal traits, such as extra-large wisdom teeth.

The jawbone was found in a cave in 2002 and has intrigued experts ever since.

The new study bolsters other experts' claims that interbreeding between Neanderthals and humans didn’t just take place in the Middle East, as previously thought.

In fact, the discovery shows that interbreeding took place shortly before the Neanderthals died out, approximately 39,000 years ago.

Last year, a high profile study led by the University of Oxford found that Neanderthals and modern humans both lived in Europe at the same time for 5,400 years.

Experts claimed Neanderthals disappeared at different times instead of being suddenly replaced by modern humans as previously thought.

They used dating evidence for 200 bone, charcoal and shell samples from 40 key European sites to prove the two groups overlapped for a significant period of time and make the first timeline showing when the last Neanderthals died out.

Because they and modern humans overlapped for a significant period, there was ‘ample time’ for interaction and interbreeding, experts said.

Professor Chris Stringer, Research Leader in Human Origins, the Natural History Museum, London said that interbreeding probably occurred soon after small groups of modern humans began to leave their African homeland about 60,000 years ago.

It is thought Neanderthals died out because they were unable to compete with our ancestors for food and resources but some ‘may have survived in dwindling pockets of Europe’ for several thousand years before becoming extinct.

Last year, a high profile study found that Neanderthals and modern humans both lived in Europe at the same time for 5,400 years, disrupting the linear idea of the march of progress (illustrated)

Experts claimed Neanderthals disappeared at different times instead of being suddenly replaced by modern humans as previously thought, based on samples (pictured) from sites that ranged from Spain to Russia