Metagenomic analysis is a highly promising technique in paleogenetic research that allows analysis of the complete genomic make-up of a sample. This technique has successfully been employed to archaeological sediments, but possible leaching of DNA through the sequence limits interpretation. We applied this technique to the analysis of ancient DNA (aDNA) from Late Quaternary stalagmites from two caves in Western Georgia, Melouri Cave and Solkota. Stalagmites form closed systems, limiting the effect of leaching, and can be securely dated with U-series. The analyses of the sequence data from the Melouri Cave stalagmite revealed potential contamination and low preservation of DNA. However, the two Solkota stalagmites preserved ancient DNA molecules of mammals (bear, roe deer, bats) and plants (chestnut, hazelnut, flax). The aDNA bearing layers from one of the two Solkota stalagmites were dated to between ~84 ka and ~56 ka BP by U-series. The second Solkota stalagmite contained excessive detrital clay obstructing U-series dating, but it also contained bear bones with a minimum age of ~50 BP uncalibrated years and ancient DNA molecules. The preservation of authentic ancient DNA molecules in Late Quaternary speleothems opens up a new paleogenetic archive for archaeological, paleontological and paleoenvironmental research.
Bibliographical noteFunding Information:
The research presented here was supported by a New Interdisciplinary Initiatives Fund grant (SF1362) to MCS by the University College Dublin. Further support came from a Government of Ireland Postdoctoral Fellowship to MCS (GOIPD/2015/775), a Medical Trainee PhD Scholarship, Anatomy, School of Medicine, University College Dublin awarded to TCC and from the Moshe and Bina Stekelis Foundation and Moshe Stekelis Chair in Prehistoric Archaeology for excavation at Satsurblia Cave in 2016 to ABC, hosting our field expedition. We are grateful to the excavation team of Satsurblia, the people of Kumistavi and the Georgian State Museum. We further would like to thank Mick Murphy from the UCD School of Earth Sciences for assistance with the U-series lab work and Susanna Sawyer from Department of Evolutionary Anthropology, University of Vienna, for assistance with sequencing data interpretation. Figure 1 was created with ASTER GDEM, a product of METI and NASA, and with help from R. C. Power, Max-Planck Institute of Evolutionary Anthropology. We are grateful to S. Tüpke and the Max-Planck Institute of Evolutionary Anthropology for making the silhouettes in Fig. 6.
© 2019, The Author(s).
ASJC Scopus subject areas