In a typical analysis, scientists have discovered that a protein found in saliva holds evidence that ancient Africans may have engaged in ‘sexual rendezvous’ with a ‘ghost’ species of archaic humans.
According to the experts, interbreeding was not unusual among early hominin species – but, with no fossils of the mysterious species in question, it’s considered a ‘ghost.’
Omer Gokcumen, PhD, an assistant professor of biological sciences in the University at Buffalo College of Arts and Sciences, says, "It seems that interbreeding between different early hominin species is not the exception -- it's the norm".
"Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva", he says. "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."
The team examined the MUC7 gene in more than 2,500 modern human genomes. The result that came out astonished the researchers as a group of genomes from Sub-Saharan Africa had a version of the gene that was wildly different from versions found in other modern humans.
The study concluded that MUC7 appears to influence the makeup of the oral microbiome, the collection of bacteria within the mouth. The evidence for this came from an analysis of biological samples from 130 people, which found that different versions of the MUC7 gene were strongly associated with different oral microbiome compositions.
The research is published in the journal Molecular Biology and Evolution.