Hello to some of our long-lost relatives

SCIENTISTS believe they have found evidence of a “ghost” species of archaic human in the saliva of people living in sub-Saharan Africa.

The find suggests that humans and a close relative may have interbred in the past.

“Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva. When we looked at the history of the gene that codes for the protein, we see the signature of archaic admixture in modern-day sub-Saharan African populations,” explained Omer Gokcumen, an assistant professor of biological sciences at the University of Buffalo College of Arts and Sciences, in a statement.

The statement issued by the University of Buffalo in the US said that the scientists made the discovery while researching the MUC7 protein.

This gene is responsible for giving saliva its slimy consistency. While the team was studying the MUC7 gene they found that a group of genomes from sub-Saharan Africa had a version of the gene that was remarkably different from other modern humans.

Their research appeared yes- terday in the journal Molecular Biology and Evolution.

“Based on our analysis, the most plausible explanation for this extreme variation is archaic introgression – the introduction of genetic material from a ‘ghost’ species of ancient hominins,” Gokcumen said in the statement issued by the university.

“This unknown human relative could be a species that has been discovered, such as a subspecies of Homo erectus, or an undiscovered hominin.

“We call it a ‘ghost’ species because we don’t have the fossils.”

Through calculating the rate at which genes mutate, the team believes that this inbreeding between humans and this ghost species could have occurred as recently as 150 000 years ago.

In recent years there has been growing evidence that humans and hominin species interbred.

Genetic studies have revealed that modern humans had possible trysts with Neanderthals and Denisovans.

Earlier this year scientists revealed that fossils belonging to Homo naledi were dated between between 335 000 and 236 000 years ago – thus making the hominin a “contemporary” of modern humans.