RADAR · Recovery of Ancient DNA from Arcaheological Residues

Final Activity Report Summary - RADAR (Recovery of Ancient DNA from Archaeological Residues)

Whilst shapes and decorations of ancient pottery have been extensively studied by archaeologists for decades, there has been much less interest in understanding what pots were actually used for. However, chemical and molecular analysis of organic residues associated with archaeological pottery and other artefacts can bridge this gap and potentially enlighten many past human activities regarding diet, nutrition and exploitation of the environment. Recently, analysis of fats from archaeological cooking pots dating to several thousand years before Christ (BC) has provided useful information, particularly concerning the exploitation of animal products. Nevertheless, this methodological approach is limited; fats do not vary very much between species and are at very low concentration in non-animal products. In this fellowship, I focused on extending the scope of this field by commencing investigations into the survival of deoxyribonucleic acid (DNA) on archaeological ceramics. DNA is a much more informative biomolecule and can potentially provide detailed information on the different types of foods that were used in the past. Virtually nothing is known about the survival of DNA on ceramics so I began by designing some simple experiments which involved repeatedly heating and storing cow's milk and beef in a range of different experimental pots and then burying them for various periods of time under controlled conditions. I then tried a range of methods to observe if DNA could be recovered and sequenced to identify the original contents of the pot and to monitor how these molecules degraded through time. In the latter research part I adapted the methods for analysis of ethnographic pots, i.e. recent pots that had been used in a range of different everyday activities, and archaeological ceramics. My first goal was to examine whether DNA survived the cooking process. By designing a quantitative DNA assay, I observed similar, very high, amounts of bovine DNA on ceramics used to boil milk and beef and those used to store milk. However, DNA from the pots that had been heated was slightly more damaged. The second goal was to test whether DNA survived the burial environment. I generally found that DNA was lost very quickly, within four years, during the experimental burial and that any residues that did remain became very difficult to extract. I tried extractions with a range of different chemicals, none of which overcame these problems sufficiently, although some success was achieved at a late project stage using a relatively mild extraction procedure. It was though obvious that the vast majority DNA was lost by both microbial degradation and leaching in the wet soils that the pots were buried in. Nevertheless, when I began analysing ethnographic pots which were much older, although unburied, I found that undamaged DNA survived and could be used to identify the species of foods that were originally cooked in the pots. This led to additional research into much older archaeological pottery from very dry environments, which could be the best source of ancient DNA.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз