Researchers discovered by chance the DNA of a "ghost species" in the genetic material of early humans.
University of Buffalo scientists have found that early humans mated with a currently unknown "ghost species." "Crossbreeding between different early human species was not the exception but the norm," said biologist Omer Gokcumen.
The researchers found the indication in a salivary protein gene.
Previous studies have found that the ancestors of modern humans in Asia and Europe mingled with other early human species. The most famous representatives among them is the Neanderthal man or the Denisova man.
The researchers around Omer Gokcumen from the University of Buffalo arrived at their conclusions by chance. Actually, the research team wanted to investigate the origin of the protein MUC7 in a study. This protein gives our saliva its slimy texture. "For the production of the MUC7 protein a genetic inheritance is responsible, which has interesting variations in humans," the researchers report.
They studied the MUC7 gene in a total of about 2500 genomes of modern humans. They found that the samples from sub-Saharan Africa contained a completely different version of the gene than was found in other modern humans.
New species or just an old acquaintance?
The most plausible explanation for this extreme variation is the introduction of genetic material from a "ghost" species of earlier hominins. This could be Homo erectus. However, it could just as well be a completely different - and still undiscovered - way for the inheritance.
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The researchers therefore currently refer to them as a ghost species, as they have not yet discovered any fossils.
Given the rate at which genes mutate in the course of evolution, the team was also able to draw conclusions about when the weird MUC7 gene was crossed.
Thus, it seems the mixing between the ancestors of today's Sub-Saharan populations and the mysterious human species, which there apparently still existed parallel, came about some 150,000 years ago.
Their findings were published in the journal ,,Molecular Biology and Evolution''.
Of course, the results now require further investigation - but we can be curious as to where this interesting story leads us.