How teeth became the key to the past
In the world of science, every detail matters. Even those hidden in a thousand-year-old tooth enamel. The study described in Proceedings of the National Academy of Sciences (PNAS) sheds new light on prehistoric communities of the Nile Valley and provides us with unique information about the biological and cultural relationships between peoples of ancient North-Eastern Africa.
Thanks to the international cooperation between twenty researchers from twelve European institutions (Polish, German, British, French, Italian, Czech, Swiss), one American university, and years-long support from the Egyptian and Sudanese authorities, the remains of 88 individuals from thirteen archaeological digs from southern Egypt and Sudan were analyzed. The changes in population structure during the period of transition from hunting and gathering to the first Neolithic communities were examined.
The latest article in the Proceedings of the National Academy of Sciences, co-authored by dr hab. Marta Osypińska from the University of Wrocław, discusses the analysis of the enamel–dentine junction. Dr hab. Osypińska laughs, saying, “The analysis may reveal who traversed the Middle Nile Valley when GPS was unavailable, cows were worshipped rather than consumed, and the night sky served as the most reliable map.”
She adds, “The article examines the traces of prehistoric migrations found in teeth, which we have deciphered.”
For a long time, the absence of paleogenetic data hindered the reconstruction of the history of the population of the Nile Valley. However, the new research shows that the analysis of the inner structure of teeth can provide incredibly precise information about the biological transformations of humanity.
The morphology of teeth allows us to discover the evolutionary history of a region on a microevolutionary level. The formulated methodology paves the way for a detailed phylogenetic analysis of human populations, especially in areas where ancient DNA is not well-preserved.
Thanks to modern X-ray imaging techniques, the mystery of the transition from hunting and gathering to farming in Sub-Saharan Africa has been unraveled. The analysis of inner tooth structures revealed previously unknown aspects of migration and the processes that led to the emergence of food production in the Nile Valley. Osypińska highlights, “It grants us a brand new view of this crucial moment in the history of humanity.”
The researchers assert that this is the first accurate biological evidence of migration and population replacement in the Nile Valley, particularly in prehistory, that is, before the oldest civilizations in our region began to form.
The research, which spans fourteen thousand years of Sub-Saharan Africa’s population history, thoroughly covers the key period: the emergence of food production practices in the Nile Valley.
Dr hab. Marta Osypińska states, “Studies concerning teeth perfectly align with the main findings of my article, which was published two weeks ago in the most prestigious archaeological journal, Journal of Archaeological Science. In that article, we discussed migrations based on archaeological data from Sudan, the beginnings of cattle raising, and the peoples of specific material cultures living in 8000 B.C.”
The involvement of our archaeologist with the team working on the article for PNAS pertained to two Early Holocene archaeological sites in Sudan: Affad and Letti, which she was investigating. The researcher explains, “Both of the sites are located in a crucial region (often referred to as the Pan-African crossroad), in the Great Bend of the Nile, where the two essential migration trails in the history of Africa converge: the Nile Valley (N-S trail) and the so-called wadi, ephemeral streams that connect Africa’s W-E line. In summary, the research presented in the article demonstrates that the so-called Neolithic Revolution in Africa, involving the beginnings of food production, did not initiate as a “skill evolution.” Instead, it “migrated” to the Middle Nile Valley with peoples who were morphologically distinct from ancient hunter-gatherers and proto-herders, and who were displaced into vast regions that gradually experienced desertification.
The appearance of food production approximately ten thousand years ago constituted one of the most crucial turning points in the history of humankind. This process began gradually between the sixth and fifth millennia B.C. in the Nile Valley, in the region of today’s southern Egypt and Sudan. As presented by dr hab. Osypińska in her recent study, published in the Journal of Archaeological Science, attempts at domesticating cattle in Africa had been taking place since the eighth millennium, and had happened independently of those in the Middle East. Despite numerous archeological discoveries, until now we lacked unambiguous evidence that would allow us to assess the peoples that participated in this crucial transformation, which was the prevalence of stationary animal husbandry and crop cultivation.
What makes the analysis of teeth so groundbreaking? Their inner structure, especially the enamel–dentine junction, is highly affected by genetic liability. What that means is that even in the DNA material is absent, microtomography of teeth allows the reconstruction of biological connections between the prehistoric peoples on a microevolutionary scale.
The coordinators and instigators of this research were Nicolas Martin and Isabelle Crevecoeur from University of Bordeaux, who, using high-resolution X-ray imaging (microtomography), analyzed the inner structure of teeth, particularly the junction between enamel and dentine (the tissues that create teeth).
PNAS is among the most prestigious journals in the world, and can be placed alongside Science and Nature. However, archeologists rarely publish their works there, as the subjects which are preferred are connected with the most significant accomplishments of the sciences. Therefore, the articles are usually concerned with genetics, physics, biology, medicine, or climatology.
“It is the first publication of the Institute of Archeology of the University of Wrocław in PNAS, as well as the first publication concerning the prehistory of Africa co-written by Polish archeologists, however, certainly not the last,” promises dr hab. Marta Osypińska. “We are thrilled that the findings of research conducted by a team I got to be a part of were appreciated internationally.”
Written by: Katarzyna Górowicz-Maćkiewicz
Date of publication: 4.04.2025
Added by: M.J.
Translated by Marta Kawik (student of English Studies at the University of Wrocław) as part of the translation practice.
