Several anthropoids – Australopithecus africanus, Strong Paranthropusearly homo sp., Gigantopithecus black, Pongo sp., Palso sp., Neanderthal manAnd wise man — have been continuously exposed to lead for 2 million years, contradicting the idea that lead exposure is a purely modern phenomenon, according to a new analysis of fossil teeth from regions of Africa, Asia, Oceania and Europe.
Human exposure to lead today compared with our ancestors. Image credit: J. Gregory/Mount Sinai Health System.
“Our data shows that lead exposure was not just a product of the Industrial Revolution – it was part of our evolutionary landscape,” said Professor Renaud Joanne-Boiau, a researcher at Southern Cross University.
“This means that our ancestors' brains developed under the influence of a potent toxic metal, which may have shaped their social behavior and cognitive abilities over thousands of years.”
Using precise, validated laser ablation microspatial sampling protocols, the authors analyzed 51 fossil specimens from Australopithecus africanus, Strong Paranthropusearly homo sp., Gigantopithecus black, Pongo sp., Palso sp., Neanderthal manAnd wise man.
They found clear signals of episodic lead exposure in 73% of the samples (71% in hominins). Australopithecus, ParanthropusAnd homo).
Some of the geologically oldest specimens are – Gigantopithecus black Estimated to originate from the early (1.8 million years ago) and middle Pleistocene (1 million years ago), they show repeated occurrences of lead exposure separated by periods of negligible lead uptake.
The researchers also turned to the lab to find out how this ancient exposure might have affected brain development.
Australopithecus africanus. Image credit: J.M. Salas / CC BY-SA 3.0.
Using human brain organoids (miniature, lab-grown brain models), they compared the effects of lead on two versions of a key developmental gene called NEW1a gene known to control gene expression upon exposure to lead during neurodevelopment.
Modern human version NEW1 is different from what is found in Neanderthals and other extinct hominids, but until now scientists did not know why this change occurred.
When organoids containing archaic NEW1 were exposed to lead and exhibited significant impairments in activity FoxP2 – expressing neurons in the cortex and thalamus, areas of the brain that are critical for the development of speech and language.
This effect was much less pronounced in modern organoids. NEW1 option.
“These results show that our NEW1 The variant may have provided protection against the harmful neurological effects of lead,” said UC San Diego professor Alisson Muotri.
“This is an extraordinary example of how environmental pressure, in this case lead toxicity, could cause genetic changes that improved survival and our ability to communicate through language, but which now also influence our vulnerability to modern lead exposure.”
Artist's impression of the group Gigantopithecus black in a forest in southern China. Image credit: Garcia/Joannes-Boyo, Southern Cross University.
Genetic and proteomic analyzes in the study showed that lead exposure in archaic organelles disrupted pathways involved in neural development, social behavior and communication.
Modified FoxP2 The activity, in particular, points to a possible link between ancient lead exposure and the evolutionary refinement of language abilities in modern humans.
“This study shows how environmental influences have shaped our evolution,” said Professor Manish Arora, a researcher at the Icahn School of Medicine at Mount Sinai.
“From an interspecies competition perspective, the observation that toxic exposure can provide an overall survival advantage offers a new paradigm for environmental medicine to study the evolutionary roots of disorders associated with environmental exposure.”
study was published in the magazine Achievements of science.
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Renaud Joan-Boillot etc.. 2025. Effects of periodic lead exposure on hominid brain evolution. Achievements of science 11 (42); doi: 10.1126/sciadv.adr1524
