Fossil avian eggshell preserves ancient DNA
Charlotte L. Oskam1, James Haile2,3, Emma McLay1, Paul Rigby4, Morten E. Allentoft1,5, Maia E. Olsen3, Camilla Bengtsson3, Gifford H. Miller6,7, Jean-Luc Schwenninger8, Chris Jacomb9, Richard Walter9, Alexander Baynes10, Joe Dortch11, Michael Parker-Pearson12, M. Thomas P. Gilbert3, Richard N. Holdaway5, Eske Willerslev3 and Michael Bunce1,*
Author Affiliations
1Ancient DNA Laboratory, School of Biological Sciences, Murdoch University, Perth, Western Australia 6150, Australia
2Ancient Biomolecules Centre, University of Oxford, Oxford OX1 3PS, UK
3Centre for GeoGenetics, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
4The Centre for Microscopy, Characterization and Analysis, The University of Western Australia, Perth, Western Australia 6009, Australia
5School of Biological Sciences, University of Canterbury and Palaecol Research Ltd, Christchurch 8041, New Zealand
6Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, CO 80309-0450, USA
7Department of Geological Sciences, University of Colorado, CO 80309-0450, USA
8Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK
9Southern Pacific Archaeological Research, Department of Anthropology, University of Otago, Dunedin 9054, New Zealand
10Western Australian Museum, Locked Bag 49, Welshpool DC, Western Australia 6986, Australia
11Archaeology, University of Western Australia, Perth, Western Australia 6008, Australia
12Department of Archaeology, University of Sheffield, Sheffield S1 4ET, UK
*Author for correspondence (m.bunce@murdoch.edu.au).
Abstract
Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful isolation and amplification of DNA from fossil eggshell up to 19 ka old. aDNA was successfully characterized from eggshell obtained from New Zealand (extinct moa and ducks), Madagascar (extinct elephant birds) and Australia (emu and owl). Our data demonstrate excellent preservation of the nucleic acids, evidenced by retrieval of both mitochondrial and nuclear DNA from many of the samples. Using confocal microscopy and quantitative PCR, this study critically evaluates approaches to maximize DNA recovery from powdered eggshell. Our quantitative PCR experiments also demonstrate that moa eggshell has approximately 125 times lower bacterial load than bone, making it a highly suitable substrate for high-throughput sequencing approaches. Importantly, the preservation of DNA in Pleistocene eggshell from Australia and Holocene deposits from Madagascar indicates that eggshell is an excellent substrate for the long-term preservation of DNA in warmer climates. The successful recovery of DNA from this substrate has implications in a number of scientific disciplines; most notably archaeology and palaeontology, where genotypes and/or DNA-based species identifications can add significantly to our understanding of diets, environments, past biodiversity and evolutionary processes.
ancient DNA, extinct birds, palaeontology, archaeology, eggshell
Footnotes
Received November 5, 2009.
Accepted February 19, 2010.
© 2010 The Royal Society
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