NEANDERTHAL adaptations to European weather may have influenced racial differences in people living today, new research suggests.

Scientists who analysed data on genetics, health, lifestyle habits and physical appearance from more than 112,000 Britons found evidence of Neanderthal influences on skin and hair colour.

Neanderthal DNA – introduced by interbreeding many thousands of years ago – also appeared to affect mood and sleeping patterns.

Earlier studies suggested that human genes involved in skin and hair biology were strongly influenced by DNA from the extinct human sub-species, but it was not clear how.

Lead scientist Dr Janet Kelso, from the Max Planck Institute for Evolutionary Anthropology in Germany, said: "We can now show that it is skin tone, and the ease with which one tans, as well as hair colour that are affected."

Because Neanderthal alleles – genetic variants – are relatively rare, the researchers needed data from a particularly large number of people.

They found the information they were looking for from more than 112,000 participants in the UK Biobank pilot study.

The Biobank not only holds a mass of genetic data, but also information relating to physical appearance, diet, sun exposure, behaviour and disease.

Many of the Neanderthal influences on the modern human genome, including those affecting skin pigmentation and hair colour, were linked to grey European weather, said the researchers.

When modern humans arrived in Eurasia around 100,000 years ago, Neanderthals had already been living there for thousands of years.

Both groups are generally thought to have started their evolutionary journey in sunny Africa.

By the time our ancestors made an appearance Neanderthals would have had a long period in which to adapt to year-round overcast skies in Europe.

A key adaptation to less sun is a fairer complexion that needs less protection from burning ultraviolet rays and makes the most of the skin's ability to manufacture vitamin D when exposed to sunlight.

The team wrote in the American Journal of Human Genetics: "Skin and hair colour, circadian rhythms and mood are all influenced by light exposure.

"We speculate that their identification in our analysis suggests that sun exposure may have shaped Neanderthal phenotypes and that gene flow into modern humans continues to contribute to variation in these traits today."

One unexpected finding was that Neanderthals appeared to differ in hair and skin colour just as much as modern humans.

Another group of researchers led by Dr Kay Prufer, from the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany, reported genetic findings from the bones of a Neanderthal female found in a Croatian cave.

The individual lived in Vindija cave roughly 52,000 years ago. She is thought to have shared a maternal ancestor with two of three other Neanderthals from the cave who were also genetically sequenced.

This study, published in the journal Science, also highlighted "a wealth" of gene variants that had passed from Neanderthals to modern humans alive today.

They included DNA sequences related to "bad" cholesterol and vitamin D levels, eating disorders, visceral fat accumulation, rheumatoid arthritis, and schizophrenia.

The evidence suggested that people of non-African heritage today had DNA that was 1.8 per cent to 2.6 per cent Neanderthal. This is higher than previous estimates of 1.5 per cent to 2.1 per cent.

Neanderthals went extinct about 30,000 years ago, possibly because they could not compete with "modern" humans for food and resources.

A third study, also reported in Science, indicates that early modern humans recognised the dangers of interbreeding 34,000 years ago and actively tried to avoid it.

This is one cultural habit that may have set them apart from Neanderthals and given them a survival advantage.

Researchers came to the conclusion after examining DNA from the remains of anatomically modern humans dating back to the Upper Palaeolithic period from the Sunghir burial site in Russia.

The four male individuals were unrelated to one another and possessed no genetic signatures of interbreeding, despite being part of a small hunter-gatherer population.

Senior author Professor Eske Willerslev, who holds posts at both Cambridge University and the University of Copenhagen, said: "What this means is that even people in the Upper Palaeolithic, who were living in tiny groups, understood the importance of avoiding inbreeding.

"The data that we have suggest that it was being purposely avoided.

"This means that they must have developed a system for this purpose. If small hunter-gatherer bands were mixing at random, we would see much greater evidence of inbreeding than we have here."