The hominin or hominini species refers to primates, more specifically gorillas.
Researchers at the University of California, San Diego have documented that over time the hominin split from chimpanzees six million years ago. However, before this process of evolution, hominins carried origins of human herpes simplex (HSV) 1 and 2.
When hominins evolved to the Homo Erectus – modern humans 1.6 million years ago, both strains of the disease were also included in our DNA.
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Approximately two-thirds of the human population is infected with at least one herpes simplex virus. The viruses are most commonly presented as cold sores on the mouth or lips or blisters on the genitals.
“Humans are the only primates we know of that have two herpes simplex viruses,” said Joel O. Wertheim, an assistant research scientist at the UC San Diego AntiViral Research Center and lead author of the study. “We wanted to determine why.”
“The researchers compared the HSV-1 and HSV-2 gene sequences to the family tree of simplex viruses from eight monkey and ape host species. Using advanced models of molecular evolution, the scientists were able to more accurately estimate ancient viral divergence times. This approach allowed them to determine when HSV-1 and HSV-2 were introduced into humans with far more precision than standard models that do not account for natural selection over the course of viral evolution.”
An artist’s impression of the early hominin Graecopithecus freybergi in its savannah home in ancient Greece
“The viral family tree showed that HSV-2 was far more genetically similar to the herpes virus found in chimpanzees. This level of divergence indicated that humans must have acquired HSV-2 from an ancestor of modern chimpanzees about 1.6 million years ago, prior to the rise of modern humans roughly 200,000 years ago.”
Scientists from Cambridge and Oxford Universities respectively conducted their own investigation and were able to determine more enlightening news.
Parathropus boisei or P. boisei was a heavyset human-like species that walked on two legs with a smallish brain and dish-like face is the main culprit.
P. boisei is said to have likely ate infected ancestral chimpanzees, in an area encompassing the African Savannah and forests then passed the pathogens onto human beings.
“Once this virus gains entry to a species it stays, easily transferred from mother to baby, as well as through blood, saliva and sex,” explained study co-author Dr. Charlotte Houldcroft, from the University of Cambridge.
Dr. Houldcroft and her team used data ranging from fossil finds to herpes DNA and ancient African climates to determine the origins of the disease.
Houldcroft went on to say, “the genital herpes virus would have crept across Africa the way it creeps down nerve endings in our sex organs – slowly but surely.”
Since HSV1, the kind that causes cold sores was the only strain present in the chimpanzees, HSV2 came about by adapting to mucosal niches found in the genitals.
“Herpes infect everything from humans to coral, with each species having its own specific set of viruses,” said Dr. Houldcroft.
