A new specialist study comes with absolutely shocking information. A substance that today is poisonous to the human body, with serious health consequences if ingested, may actually represent the secret of human intelligence and articulate speech, researchers say.
Neanderthals would have ingested lead PHOTO shutterstock
Archaeological discoveries and anthropological research indicate that in parallel with homo sapiens, i.e. modern man, on the surface of the Earth, other similar species of hominids lived. It is enough to mention the Neanderthal Man or the Denisovans. Not to mention the fact that other hominid species went extinct before modern man held supremacy. What was the secret of homo sapiens survival in a hostile environment?
One asset, experts say, was a genetic specialization that allowed it to cope with sporadic lead poisoning, a particularly poisonous metal that was abundant in nature and occasionally ingested by hominids, experts say. Unlike homo sapiens, the other hominid species would not have possessed the genes necessary to resist intoxication. Because of this, he would have presented cognitive problems and even disappeared. At least that's what a new study published in the journal Science Advances shows, by a group of researchers from the University of California, San Diego and Southern Cross.
Man exposed for over two million years to a poisonous metal
Lead poisoning has long been presented as a problem of the contemporary world. Lead reaches humans through industrial pollution or car fuel emissions, among other sources. Lead poisoning is extremely serious in humans. It mainly affects the developing brain. Even low-dose exposure can affect cognition and communication. For example, children who are chronically exposed to accidental lead poisoning also have a lower IQ. Specialists say, however, that this problem of lead poisoning is not contemporary.
On the contrary, as the mentioned study shows, hominids have been exposed to poisoning with this metal for over 2 million years. “Here, we demonstrate, using fossil teeth, that several hominids (Australopithecus africanus, Paranthropus robustus, early Homo sp., Gigantopithecus blacki, Pongo sp., Homo neanderthalensis, and Homo sapiens) were consistently exposed to lead for over 2 million years, contradicting the idea that lead exposure is exclusively a phenomenon modern”specify the specialists in the work “Impact of intermittent lead exposure on hominid brain evolution”.
Obviously, hominids did not ingest or inhale nox, but they could become poisoned with lead from the natural environment. More specifically, prehistoric lead was taken from soil, volcanic dust, and water that flowed through mineral-rich caves. Including Neanderthal Man and Denisovans (a species or subspecies of archaic man) were exposed to lead ingestion through the same sources. The team of American researchers conducted several studies on 51 fossilized teeth from Homo sapiens, Neanderthals and extinct primates such as Gigantopithecus blacki.
The fossils, which date from 100,000 to 1.8 million years ago, have been found in Africa, Asia and Europe. The scientists detected lead in 73 percent of the samples using high-precision laser ablation geochemistry, showing that hominids were chronically exposed to the metal.
Human ancestors affected by lead poisoning
The effects of lead poisoning are known, as I have shown above. And hominids were not immune to them, especially in areas where the concentration was higher and exposure was prolonged. In particular, most likely, it was about the water from the caves, loaded with this metal, drunk daily. Especially the Neanderthals, they used the same water sources, the same shelters for long periods. Lead toxicity may have shaped our evolution. Especially the one related to brain and language development.
“Lead is highly toxic, especially to the developing brain. Even at low doses of exposure it can impair cognition and communication, two skills necessary for survival and cooperation. Researchers have wondered why early Homo sapiens were able to thrive in such conditions while Neanderthals and other relatives died out.”say those from Archeology News.
“Deficits in intelligence, behavior, and emotional performance have been widely observed in lead-exposed human populations and in animal models. However, no clear molecular mechanisms have been identified linking lead exposure to hominid evolution, particularly its role in shaping group dynamics, which we address here.”the researchers state in the study.
The gene that helped us survive lead poisoning
Following the research carried out, especially by comparison between archaic hominids and modern man, the specialists came to the conclusion that the difference was made by a single gene. It is about the gene called NOVA 1. Effectively this gene regulates brain development and normal communication. It was found that we have this gene in common with all other hominids. It's just that in homo sapiens it's a slightly different version compared to Neanderthals, Denisovans and other hominids. As a kind of subtle improvement of this gene. That is, the difference is made by only one base pair in DNA. This small difference, however, has brought us to this day, the dominant species of Earth. This small difference within the same gene has made us, as an adaptation to the environment, more resistant to lead poisoning. That is, we tolerate higher amounts of lead than other hominids without it affecting us. To demonstrate this, the researchers used brain organoids in the laboratory, mimicking both archaic versions of hominids and modern humans. The results were amazing.
“To test its effect, the researchers grew tiny brain 'organoids' in a lab using both modern and ancient versions of the gene, then exposed them to lead. Organoids with modern human NOVA1 were more resistant to the effects of lead, maintaining healthy brain cell growth. The ancient variant, however, showed disruption of the FOXP2 gene, which is essential for speech and language development. This suggests that the human-specific mutation of the NOVA1 gene may have protected our ancestors' brains, allowing language and complex communication to flourish.”Archeology News claims.
Being less affected or not at all affected by the ingestion of lead, in the quantities taken from nature (obviously small), homo sapiens managed to survive the environmental challenges.
“Lead exposure on human brain organoids carrying the archaic NOVA1 variant disrupts the expression of FOXP2 in cortical and thalamic organoids, a gene crucial to the development of human speech and language skills. Altogether, fossil, cellular, and molecular data support that lead exposure may have contributed to the impact of social and behavioral functioning during evolution, providing probably a survival advantage for modern humans”show the specialists in the study.
