Kirsty Penkman

2020 United Kingdom Award Winner — Faculty

Current Position:
Reader in Analytical Chemistry

Institution:
University of York

Discipline:
Analytical Chemistry

Recognized for: The revitalization and legitimization of amino acid racemization as an analytical tool for dating ancient fossils.

Areas of Research Interest and Expertise: Analytical Chemistry, Biomolecular Archaeology, Environmental Geochemistry, Geochronology

Previous Positions:

MChem, University of Oxford
Pre-doctoral Fellow, University of Bergen, Norway
PhD, University of Newcastle-upon-Tyne (Advisors: Dr. Matthew Collins & Dr. Darrel Maddy)
Postdoctoral Researcher, University of York (Advisor: Professor. Matthew Collins)
Postdoctoral Fellow, University of York

Research Summary:

Kirsty Penkman, PhD, has resurrected an analytical approach called amino acid racemization (AAR) for the dating of fossils that are older than the limit of radiocarbon dating (~50,000 years). Originally developed in the 1960s, AAR exploits the fact that after an organism dies, specific amino acids within a protein begin to undergo a slow change in the three-dimensional arrangement of their atoms. This process is called racemization and takes place in a predictable manner over time, such that analysis of the ratio of unracemized to racemized amino acids can reveal the approximate age of a fossil. Unfortunately, exposure to changing environmental conditions—including fluctuations in pH, temperature, and relative humidity—can affect the rate at which proteins racemize, and thus lead to inaccurate ages. Penkman has shown that through careful isolation of certain fossil proteins that have remained isolated from the environment, one can reliably apply AAR for geochronology to date back at least 3 million years. Not only is this a time period that is very difficult to date, it is a critical period for understanding climate, as it is characterized by a succession of glacial (cold) and interglacial (warm) episodes. With accurate dates, its rich fossil record can start to reveal how plants and animals, including humans, responded to marked climate change. To date, Penkman has successfully applied this technique to accurately date ancient corals, ostrich eggshells, mollusk shells, and most recently tooth enamel, which has significantly extended the applicability of AAR to include the mammalian fossil record. The chronologies from these studies have revealed important insights into the migration and technological development of early humans, changes in climate throughout Earth’s history, and evolutionary pressures that have led to the diversification of living organisms over time.

"Having always loved chemistry, but also been fascinated by the past (both our human history and that of our Earth), I feel enormously lucky to be able to combine both in my work. My research focuses on the analysis of fossil biomolecules: their pathways of degradation, methods for their detection, and how these molecules can inform us of an organism’s life and death history. I am tremendously honoured by the Blavatnik award, and it is thanks to my wonderful collaborators who have been integral to this research. Working closely with earth scientists and archaeologists has helped push the analytical science forward, whilst advancing our understanding of our earth's history."

Key Publications:

1. K.E.H. Penkman, D.S. Kaufman, D. Maddy, M.J. Collins. Closed-system Behavior of the Intra-crystalline Fraction of Amino Acids in Mollusk Shells. Quaternary Geochronology, 2008.
2. K.E.H. Penkman, R.C. Preece, D.R. Bridgland, D.H. Keen, T. Meijer, S.A. Parfitt, T.S. White, M.J. Collins. A Chronological Framework for the British Quaternary Based on Bithynia Opercula. Nature, 2011.
3. B. Demarchi, S. Hall, T. Roncal-Herrero, C.L. Freeman, J. Woolley, M.K. Crisp, J. Wilson, A. Fotakis, R. Fischer, B.M. Kessler, R. Rakownikow Jersie-Christensen, J.V. Olsen, J. Haile, J. Thomas, C.W. Marean, J. Parkington, S. Presslee, J. Lee-Thorp, P. Ditchfield, J.F. Hamilton, M.W. Ward, C.M. Wang, M.D. Shaw, T. Harrison, M. Dominguez-Rodrigo, R.D.E. MacPhee, A. Kwekason, M. Ecker, L. Kolska Horwitz, M. Chazan, R. Kroger, J. Thomas-Oates, J.H. Harding, E. Cappellini, K. Penkman, M.J. Collins. Protein Sequences Bound to Mineral Surfaces Persist into Deep Time. eLife, 2016.
4. K. High, N. Milner, I. Panter, B. Demarchi, K.E.H. Penkman. Lessons from Star Carr on the Vulnerability of Organic Archaeological Remains to Environmental Change. Proceedings of the National Academy of Sciences, 2016.

Other Honors:

In the Media:

Smithsonian.com – 1.7-Million-Year-old Rhino Tooth Provides Oldest DNA Data Ever Studied

The Yorkshire Post – The Tooth is Out There—Key to Evolution is on the Tip of Our Tongue, York Scientists Discover

Science Daily – Scientists Get a Grip on Sloth Family Tree

The Analytical Scientist - On the Dating Scene

Chemistry World – Dating the Age of Humans

The Daily Telegraph – Early Man is Traced to the Costa del Cromer

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