Various evolutionary forces shape the human skeleton


Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen explores skeletal features as an alternative to DNA analysis

Tübingen, 10.08.2023 
 
Genetic kinship analyses of human bones reach their limits if the DNA is poorly preserved or if destructive sampling is not possible. New research shows that in such cases, comparisons of the structure and shape of certain parts of the skeleton may also provide detailed information about relationships, and do so non-destructively. This is the result of a large-scale study by an international research team led by Dr. Hannes Rathmann and Professor Katerina Harvati from the Senckenberg Centre for Human Evolution and Palaeoenvironment and the Institute for Archaeological Sciences at the University of Tübingen. 
 
The team analyzed large genetic and skeletal datasets to determine the extent to which human genetic diversity worldwide is reflected in the morphology – i.e, the structure and shape – of skeletal parts. The researchers obtained the best results when comparing certain dental and cranial elements, yet they also found that some worked significantly better than others and this difference is likely the result of how they evolved. This basic research may be used as a reference in future archaeological and forensic investigations to arrive at more robust inferences when DNA analysis is not possible. The study has been published in the journal PNAS Nexus. 

 Skeletal elements preserve differing evolutionary forces

Human skeletal morphology is highly diverse and varies among individuals and populations around the globe. This diversity is the result of a complex interplay of various evolutionary forces over a long period of time. “Evolutionary biologists divide these forces into two distinct processes. A neutral process refers to mutations producing new diversity which, however, offers no direct advantages or disadvantages to the affected individuals. This new diversity then increases or decreases randomly via what is known as genetic drift within a population,” explains Hannes Rathmann. “This is contrasted with non-neutral processes, for example, when mutations do affect the fitness of an individual. As a result, the affected individuals have a greater or lesser ability to adapt to environmental factors,” he says. To draw detailed conclusions about underlying genetic kinship, he says, only skeletal elements that evolved through neutral processes should be used. 
 
In the study, the team focused on the teeth and skull, whose structures are considered to have evolved primarily through neutral processes. “Contrary to earlier assumptions, not all features in the teeth and skull reliably reflect the underlying genetic code; some are much more suitable than others,” Rathmann says. Small morphological features on the teeth, such as groove patterns in the crowns, the number and size of cusps, the shape of the roots, and the presence or absence of wisdom teeth, proved to be particularly suitable. “However, we obtained the best results, almost identical to a conventional genetic relationship analysis, when we included all features of the skull and teeth,” he says. “This is also expected, as more skeletal features provide a richer knowledge of underlying genetic information,” he adds. 

A non-destructive alternative 

Katerina Harvati, the study’s senior author, adds, “The results enhance our understanding of the origins of human skeletal diversity. They are also promising for several direct applications in archaeological and forensic investigations.” Genetic analyses are often constrained by poor DNA preservation. This is commonly the case with very old bones or those that have been exposed to a warm climate, Harvati explains. Damaging bones for DNA analyses is also often out of the question in the case of fragile material or rare finds, or due to ethical reasons. “In such cases, the non-destructive examination of skulls and teeth is a valuable alternative for tracing past population history and hominin phylogeny in archaeological contexts, for example, or for infering ancestry profiles in forensic cases. This work, therefore, has implications for the scientific community and society at large,” Harvati says. 

Publication: 
Hannes Rathmann, Silvia Perretti, Valentina Porcu, Tsunehiko Hanihara, G. Richard Scott, Joel D. Irish, Hugo Reyes-Centeno, Silvia Ghirotto, Katerina Harvati (2023): Inferring human neutral genetic variation from craniodental phenotypes. PNAS Nexus, Volume 2, Issue 7, pgad217, https://doi.org/10.1093/pnasnexus/pgad217 

 

Contact

Dr. Hannes Rathmann
wiss. Mitarbeiter

I am a postdoctoral researcher in biological anthropology, currently employed at the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen. My research focuses on human migrations, demography, and behavior in the past, utilizing computational methods and fostering interdisciplinary synergy between skeletal biology, paleogenetics, and archaeology. Additionally, I oversee the Osteological Collection within the Paleoanthropology Section of the Institute for Archaeological Sciences at the University of Tübingen.

 

My research interests include:

  • Bioarchaeology
  • Skeletal and dental variation
  • Population structure and history
  • Population and quantitative genetics
  • Bioinformatics and programming
  • Osteological collections
  • Provenance research and repatriation

 

Social media:

X: https://x.com/hannes_rathmann

Bluesky: https://bsky.app/profile/hannesrathmann.bsky.social

Research Gate: https://www.researchgate.net/profile/Hannes-Rathmann-2

ORCID: https://orcid.org/0000-0002-7830-4667

Academic / Professional Trajectory

 

2020 – Present
Post-Doctoral Researcher / Curator of the Osteological Collection
Senckenberg Centre for Human Evolution and Palaeoenvironment, Palaeoanthropology working group, University of Tübingen

2020 – 2021
Coordinator of studies and teaching
B.Sc. and M.Sc. “Paleoanthropology” and “Archaeological Sciences”, University of Tübingen

2018 – 2019
Research fellow
DFG Center for Advanced Studies “Words, Bones, Genes, Tools: Tracking Linguistic, Cultural and Biological Trajectories of the Human Past”, University of Tübingen

2014 – 2018
Ph.D. in Archaeological Sciences / Paleoanthropology (magna cum laude)
Institute for Archaeological Sciences, University of Tübingen, Supervisors: Prof. Dr. Katerina Harvati and Prof. Dr. Richard Posamentir

2015 – 2017
Doctoral scholarship
Gerda Henkel Foundation doctoral fellowship, Department of Palaeoanthropology, University of Tübingen

2011 – 2013
M.Sc. in Archaeological Sciences / Paleoanthropology (magna cum laude)

Institute for Archaeological Sciences, University of Tübingen, Supervisors: Prof. Dr. Joachim Wahl and Prof. Dr. Heinrich Härke

2008 – 2011
B.A. in Pre- and Protohistory and Medieval Archaeology (magna cum laude)

Institute for Pre- and Protohistory and Medieval Archaeology, University of Tübingen, Supervisors: Prof. Dr. Joachim Wahl and Prof. Dr. Martin Bartelheim

 

Awards, Grants & Scholarships

09/2024 – 02/2026
Research grant
Project title: “Human population history of Upper Paleolithic Europe inferred from fossil dental remains”. Funded by the Program for the Promotion of Junior Researchers of the University of Tübingen (29,350 Euro)

07/2024
Travel grant
Awarded by the German Academic Exchange Service (1,198 Euro)

03/2024
Innovation in Dental Anthropology Award
Received from the Dental Anthropology Association (DAA)

2023
Journal recognition
Recognition for the research article “Comparing individuals buried in flexed and extended positions at the Greek colony of Chersonesos (Crimea) using cranial metric, dental metric, and dental nonmetric traits”, listed among the top 10 most-cited articles in International Journal of Osteoarchaeology in 2022-2023

9/2022 – 08/2024
Research grant
Project title: “Precarious provenance — Human remains from Africa’s colonial past before 1919 in scientific collections of Baden-Württemberg (project phase 2)”. Funded by the German Lost Art Foundation and the Ministry of Science Baden-Württemberg. Granted to the Museum of the University of Tübingen in cooperation with the Osteological Collection Tübingen, State Museum of Natural History Stuttgart, State Museum of Natural History Karlsruhe, and Linden Museum Stuttgart (172,396 Euro)

9/2021 – 08/2022
Research grant
Project title: “Precarious provenance — Human remains from Africa’s colonial past before 1919 in scientific collections of Baden-Württemberg (project phase 1)”. Funded by the German Lost Art Foundation and the Ministry of Science Baden-Württemberg. Granted to the Museum of the University of Tübingen in cooperation with the Osteological Collection Tübingen, State Museum of Natural History Stuttgart, State Museum of Natural History Karlsruhe, and Linden Museum Stuttgart (74,568 Euro)

2020
Journal recognition
Recognition for the research article “Population history of southern Italy during Greek colonization inferred from dental remains”, listed among the top 10% of most read articles in American Journal of Physical Anthropology in 2018-2019

2017
Journal recognition
Recognition for the research article “Reconstructing human population history from dental phenotypes”, listed among the top 100 most read articles in Scientific Reports in 2017

01/2015 – 12/2017
Doctoral scholarship
Project title: “Interactions between Greek Colonists and Indigenous Italic Peoples in Early Iron Age Southern Italy”. Granted by the Gerda Henkel Foundation (57,850 Euro)

10 Selected Recent Publications

Will M, Rathmann H (2025). Exploring the utility of unretouched lithic flakes as markers of cultural change. Scientific Reports 15: 1571. https://doi.org/10.1038/s41598-025-85399-z

Rathmann H, Vizzari MT, Beier J, Bailey SE, Ghirotto S, Harvati K (2024). Human population dynamics in Upper Paleolithic Europe inferred from fossil dental phenotypes. Science Advances 10 (33): eadn8129. https://doi.org/10.1126/sciadv.adn8129

Beier J, Santon M, Rathmann H (2024). Estimating trauma prevalence from incomplete human skeletal remains. Scientific Reports 14: 27713. https://doi.org/10.1038/s41598-024-76231-1

Rathmann H, Perretti S, Porcu V, Hanihara T, Scott GR, Irish JD, Reyes-Centeno H, Ghirotto S, Harvati K (2023). Inferring human neutral genetic variation from craniodental phenotypes. PNAS Nexus 2 (7): pgad217. https://doi.org/10.1093/pnasnexus/pgad217

Rathmann H, Lismann S, Francken M, Spatzier A (2023). Estimating inter-individual Mahalanobis distances from mixed incomplete high-dimensional data: Application to human skeletal remains from 3rd to 1st millennia BC Southwest Germany. Journal of Archaeological Science 156: 105802. https://doi.org/10.1016/j.jas.2023.105802

Rathmann H, Stoyanov R, Posamentir R (2022). Comparing individuals buried in flexed and extended positions at the Greek colony of Chersonesos (Crimea) using cranial metric, dental metric, and dental nonmetric traits. International Journal of Osteoarchaeology 32 (1): 49-63. https://doi.org/10.1002/oa.3043

Rathmann H, Reyes-Centeno H (2020). Testing the utility of dental morphological trait combinations for inferring human neutral genetic variation. Proceedings of the National Academy of Sciences USA 117 (20): 10769-10777. https://doi.org/10.1073/pnas.1914330117

Rathmann H, Kyle B, Nikita E, Harvati K, Saltini Semerari G (2019). Population history of southern Italy during Greek colonization inferred from dental remains. American Journal of Physical Anthropology 170 (4): 519-534. https://doi.org/10.1002/ajpa.23937

Rathmann H, Reyes-Centeno H, Ghirotto S, Creanza N, Hanihara T, Harvati K (2017). Reconstructing human population history from dental phenotypes. Scientific Reports 7: 12495. https://doi.org/10.1038/s41598-017-12621-y

Reyes-Centeno H, Rathmann H, Hanihara T, Harvati K (2017): Testing modern human out-of-Africa dispersal models using dental non-metric data. Current Anthropology 58 (S17): S406-S417. https://doi.org/10.1086/694423

 

Press Material

Skulls excavated from an archaeological site.  

 

Pressemeldung menschliche Skelette

Comparison between worldwide genetic diversity and morphological diversity of skulls and teeth. The world map above shows an overview of the samples studied (A). The six graphs below show the relationships of the samples based on DNA data (B) and on various morphological skull and tooth data (C-G). A grouping of points indicates close relationship. The morphological data overall yields similar, though not identical, results to the DNA-based kinship analysis. Image