Amino acid dating of mammalian tooth enamel and its potential for building geochronologies

TY - GEN

T1 - Amino acid dating of mammalian tooth enamel and its potential for building geochronologies

AU - Dickinson, Marc

AU - Titov, Vadim V.

AU - Frolov, Pavel

AU - Tesakov, Alexey

AU - Patinglag, Laila

AU - Shaw, Kirsty

AU - Herridge, Victoria L.

AU - Lister, Adrian M

AU - Penkman, Kirsty Elizabeth Helena

PY - 2021/6/4

Y1 - 2021/6/4

N2 - Directly dating mammalian remains is extremely difficult beyond the limits of radiocarbon dating (~50 ka). One possible direct dating method is to use the predictable breakdown of proteins and amino acids in biominerals that contain closed-system protein. This has been a powerful tool for Pleistocene age estimation in calcium carbonate biominerals (back to ~2.5 Ma), but the application of this technique to mammalian remains has been challenging. Our novel method targets a proteinaceous fraction in enamel protected within the biomineral crystals (the intra-crystalline fraction), which has alleviated difficulties associated with contamination, leaching and environmental influences. Through simulated degradation experiments to investigate both the protein breakdown and the intrinsic properties of enamel’s inorganic crystal structure, we have found that an intracrystalline fraction of amino acids can be successfully isolated from enamel. The extent of intra-crystalline protein decomposition (IcPD) in proboscidean enamel has been tested against known age material from Britain, Russia and the Mediterranean, showing a strong correlation between extent of IcPD and age. It is therefore now possible to provide direct age estimation for unknown age proboscidean material from the same temperature regions. The Wisdom Teeth project is developing IcPD geochronologies using a variety of mammalian taxa (e.g. bovids and equids) from sites spanning the Plio-Pleistocene in Africa. By targeting sites of anthropological significance in regions including Lake Turkana and South Africa, it is hoped that these IcPD geochronogies will provide relative dating to aid existing understanding of human evolution. We are also investigating taphanomic alteration of fossil enamel using an array of techniques including high resolution imaging, to better understand the processes of amino acid preservation. Lastly, we are exploiting the advances in microfluidic technology to develop a “lab-on-a-chip” approach for preparation of enamel samples, with a twofold aim: firstly to reduce sample sizes from ~30 mg to ~ 1 mg, and secondly to allow IcPD dating to be undertaken outside specialist labs.

AB - Directly dating mammalian remains is extremely difficult beyond the limits of radiocarbon dating (~50 ka). One possible direct dating method is to use the predictable breakdown of proteins and amino acids in biominerals that contain closed-system protein. This has been a powerful tool for Pleistocene age estimation in calcium carbonate biominerals (back to ~2.5 Ma), but the application of this technique to mammalian remains has been challenging. Our novel method targets a proteinaceous fraction in enamel protected within the biomineral crystals (the intra-crystalline fraction), which has alleviated difficulties associated with contamination, leaching and environmental influences. Through simulated degradation experiments to investigate both the protein breakdown and the intrinsic properties of enamel’s inorganic crystal structure, we have found that an intracrystalline fraction of amino acids can be successfully isolated from enamel. The extent of intra-crystalline protein decomposition (IcPD) in proboscidean enamel has been tested against known age material from Britain, Russia and the Mediterranean, showing a strong correlation between extent of IcPD and age. It is therefore now possible to provide direct age estimation for unknown age proboscidean material from the same temperature regions. The Wisdom Teeth project is developing IcPD geochronologies using a variety of mammalian taxa (e.g. bovids and equids) from sites spanning the Plio-Pleistocene in Africa. By targeting sites of anthropological significance in regions including Lake Turkana and South Africa, it is hoped that these IcPD geochronogies will provide relative dating to aid existing understanding of human evolution. We are also investigating taphanomic alteration of fossil enamel using an array of techniques including high resolution imaging, to better understand the processes of amino acid preservation. Lastly, we are exploiting the advances in microfluidic technology to develop a “lab-on-a-chip” approach for preparation of enamel samples, with a twofold aim: firstly to reduce sample sizes from ~30 mg to ~ 1 mg, and secondly to allow IcPD dating to be undertaken outside specialist labs.

M3 - Conference contribution

BT - 9th International Symposium on Biomolecular Archaeology

T2 - 9th International Symposium on Biomolecular Archaeology

Y2 - 1 July 2021 through 4 July 2021

ER -