Scientists have provided explanation why more West Africans especially Nigerians unlike other races are better protected from developing cancers.Evidence of an unknown species of human ancestor has been found hiding in the Deoxy ribonucleic Acid (DNA)/genetic material of West African people.

Experts made the finding by analysing the human genome, looking for strings of genetic information that were out of place.This revealed an inheritance of markers from an unidentified human-like species, some of which may be of benefit to their descendants – including one, which suppresses the development of tumours.

Researchers believe an ancient species of hominin, known as Homo heidelbergensis, may be the most likely candidate for the ‘ghost’ species.The full findings of the study are available in a paper published in the online print repository bioRxiv.

Arun Durvasula and Sriram Sankararaman, researchers at the University of California, Los Angeles, United States (U.S.), made the finding. They devised a statistical method able to highlight abnormal genetic code without needing the genome of the species it was inherited from.This bypasses the need for DNA extracted from extinct African hominins as a basis of comparison.

The hotter and wetter climate on the African continent tends to destroy any preserved DNA, unlike samples of human-like species the Neanderthals and Densiovans uncovered in Europe and Asia.The statistical technique was applied to the DNA of 50 modern Yoruba who had their genetic information sequenced as part of the 1,000 Genomes Project. This established that roughly eight per cent of their DNA comes from a yet unknown ‘ghost’ species.

The Yoruba tribe of West Africa is found predominantly in Nigeria, Benin, Togo and Ghana.While Homo sapiens may be the only hominin species alive today, tens of thousands of years ago the planet was home to a variety of human and protohuman species.

As the result of interspecies breeding, some of these species’ DNA has been passed down to modern humans.Traces of Neanderthal DNA are still found in people of non-African descent and Denisovan DNA lives on in people of Asian heritage.

Researchers also learned in 2016 that the DNA of an unknown population of archaic hominins continues to exist in Pacific Island peoples.The Neanderthals and Denisovans have been ruled out of the equation, as we already have their DNA and there is no evidence to suggest they lived in Africa.

Homo heidelbergensis was a more advanced hominin living in Africa around 200,000 years ago and a more probable candidate. It could also be that the mystery DNA came from an isolated group of Homo sapiens or population of hominins that are as yet unknown to researchers.