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A 250,000-year-old Neanderthal tooth is an unprecedented record of birth, breastfeeding, illness and exposure to lead during the first three years of this child's life. Credit: Tanya Smith and Daniel Green
Researchers from the Department of Environmental Medicine and Public Health at the Icahn School of Medicine at Mount Sinai have discovered the earliest evidence of lead exposure in an extinct species resembling the 39, man 250,000 years ago.
This study is the first to report Neanderthal lead exposure and the first to use teeth to reconstruct the climate during key development events, including weaning and breastfeeding duration, determinants keys to population growth.
The results of the study will be published online in Progress of science October 31.
The international research team composed of biological anthropologists, archaeologists, Earth scientists and environmental experts measured the barium, lead and oxygen in the teeth, looking for signs of breastfeeding, weaning, chemical exposure and climatic variations on the teeth growth rings. Elementary analysis of teeth revealed short-term lead exposure during cooler seasons, possibly due to ingestion of contaminated food or water or inhalation fire containing lead.
During the development of the fetus and childhood, a new layer of teeth is formed every day. As each of these "growth rings" is formed, some of the many chemicals circulating in the body are captured in each layer, providing a chronological record of the exposure. The research team used lasers to sample these layers and reconstruct the past exposures along incremental markings, such as with the use of growth rings on a tree to determine the patterns. growth history of the tree.
A 250,000-year-old Neanderthal tooth is an unprecedented record of birth, breastfeeding, illness and exposure to lead during the first three years of this child's life. Credit: Smith et al. 2018 Scientific Progress
This evidence allowed the team to relate the development of individuals to the old seasons, revealing that a Neanderthal was born in the spring and that both Neanderthal children were more likely to be sick during periods colder. The results are consistent with the mammalian offspring model during periods of increased food availability. The duration of breastfeeding for 2.5 years in an individual is similar to the average age of weaning in preindustrial human populations. The researchers point out that they can not generalize about Neanderthals because of the small size of the study, but that their research methods offer a new approach to answering questions about long gone extinct species.
"Traditionally, people thought that lead exposure occurred in populations only after industrialization, but these results show that it happened before the release of lead in the environment "said one of the study's lead authors, Christine Austin, Ph.D. Professor at the Department of Environmental Medicine and Public Health at the Icahn School of Medicine in Mount Sinai. "Our team plans to analyze more of our ancestors' teeth and study how lead exposure may have affected their health and its potential impact on the way our body reacts to lead today." ; hui ".
"Dietary habits at the beginning of our lives have serious consequences for our health.In understanding the evolution of breastfeeding, we can help the current population to define good breastfeeding practices," he said. said Manish Arora, Ph.D., BDS, MPH, Professor and Vice President of the Department of Environmental Medicine and Public Health of the Icahn School of Medicine. "Our research team is working to apply these techniques to contemporary populations in order to study how breastfeeding alters health trajectories, including those of neurodevelopment, heart health and stroke." Other high priority health outcomes. "
"This study signals a major breakthrough in the reconstruction of ancient climates, an important factor of human evolution, as temperature and precipitation cycles have influenced the landscapes and food resources on which our ancestors s & # ## "Supported," said lead author of the study, Tanya Smith, Ph.D., associate professor at Griffith University.
Explore further:
Wild Orangutan teeth provide insight into the evolution of breastfeeding in humans
More information:
T.M. Smith el al., "Winter stress, breastfeeding and lead exposure in Neanderthal children," Progress of science (2018). advance.sciencemag.org/content/4/10/eaau9483
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