Up to four per cent of our DNA can be traced back to cavemen, researchers have claimed.

Modern humans have a varied mixture of genes, including some from Neanderthals and Denisovans, which are extinct species of humans. And scientists believe these ancient genes could have helped modern humans to adapt and thrive in different environments.

American researchers based at the University of Washington tested DNA samples from 1,500 people living all over the world to look at their genetic profiles in detail. They then used the information to put together a genome map.

They found that those with European ancestry had inherited approximately two per cent of their DNA from Neanderthals, while those from islands in the Pacific could attribute approximately four per cent of their genes to Denisovans.

The study discovered there were 126 points in the modern human genome where prehistoric genes were still found. And the researchers concluded that the fact these genes had survived so many years of evolution suggested they were beneficial to us rather than detrimental.

Genes can aid survival

The ancient genes they identified were linked to skin function and the immune system. They believe it is possible these elements of DNA were crucial in helping our ancestors survive outside of Africa and adapt to a different climate and environment.

Professor Joshua Akey, from the University of Washington School of Medicine in Seattle, said: “Our work shows that hybridisation was not just some curious side note to human history, but had important consequences and contributed to our ancestors’ ability to adapt to different environments as they dispersed throughout the world.”

The study, which has been published in Current Biology, suggests that less helpful genes will have gradually disappeared from our DNA over time.

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