Ancient DNA in ceramic artifacts
Determining original contents
|Enlarge ImageDrs. Theotokis Theodhoulou, Dimitris Kourkoumelis, Maria Hansson, and Brendan Foley investigate the original contents of "empty" amphoras, by amplyfing ancient DNA trapped in the ceramic jars. (P. Vezirtis, Ephorate of Underwater Antiquities)
|Enlarge ImageHellenic Ministry of Culture maritime archaeologist Dr. Dimitris Kourkoumelis collects a ceramic sample from the interior of a 4th century BC amphora from Chios. (Brendan Foley)
|Enlarge ImageOnly a small amount of material is needed to extract DNA. (Brendan Foley)
|Enlarge ImageMolecular biologist Dr. Maria Hansson runs a gel to detect ancient DNA in samples collected from a Classical Greek amphora. (Tom Kleindinst, WHOI)
OverviewTo read our peer-reviewed articles on ancient DNA identified in amphoras, see:
Brendan P. Foley, Maria C. Hansson, Dimitris P. Kourkoumelis, Theotokis A. Theodoulou, "Aspects of Ancient Greek Trade Re-evaluated with Amphora DNA Evidence" Journal of Archaeological Science 39 (2012):389-398 doi: 10.1016/j.jas.2011.09.025
M. Hansson and B. Foley, "Ancient DNA fragments inside Classical Greek amphoras reveal cargo of 2400-year-old shipwreck" Journal of Archaeological Science 35.5 (May 2008): 1169-1176.
For popular looks at this ongoing research program, see:
Nature Ancient Greek ships carried more than just wine
Science Will DNA Swabs Launch CSI Cargo?
ScienceNews Jars of Plenty
Boston Globe State Police DNA Techniques Unlock Mediterranean Secrets
See also Archaeology Volume 62, Number 4: July/August 2009
"The Latest Underwater Discoveries: Submerged DNA, Chios, Greece"
London Daily Telegraph: Message in a 2400-year-old bottle
Ancient DNA can reveal the original contents of empty ceramic archaeological artifacts. In 2007 we conducted proof-of-concept trials by applying molecular biology procedures to two 2400 year-old ceramic jars recovered from the Greek shipwreck located between Chios and Oinousses. Miniscule ceramic samples collected from inside the amphoras yielded short (≤100 base pair) ancient DNA fragments of olive and oregano in one jar from Chios; and DNA of the Pistacia genus, possibly P. lentiscus (mastic) in the other unattributed amphora. These preliminary results are very encouraging, and we are now working to advance these molecular archaeology techniques. The specific methods include preparation and refinement of species-specific oligonucleotide primers for chloroplast DNA markers, polymerase chain reaction, cloning, and DNA sequencing. When perfected, these ancient DNA investigations of archaeological artifacts will allow a broad range of scholars to routinely identify ceramic vessels' original contents. This opens entirely novel avenues of scientific inquiry.
This is a powerful new tool for archaeology. Ceramic artifacts are ubiquitous on terrestrial and underwater archaeological sites. In the ancient Mediterranean, specially designed ceramic shipping containers (amphoras) carried a wide range of goods. Cultures beyond the Mediterranean produced ceramic vessels for both everyday use and elaborate religious rites. For instance, people of the Mesoamerican Maya culture deposited ceramic objects in cenotes and underwater caves. Until now, determining the original contents of all these ceramic objects has been difficult, aided only occasionally by physical evidence (e.g. olive pits, hardened resins, seeds, chocolate residue) found inside excavated jars or on graffiti on their exteriors. With this DNA method, archaeologists will be able to identify artifacts' contents even when no physical remains are apparent.
As we refine this technique, we have specific objectives in mind: to establish which species can be identified by ancient DNA analyses of ceramic artifacts; to determine the factors that affect survival of ancient DNA within the ceramic matrices of artifacts; and to refine DNA retrieval methods from artifacts using different sampling techniques.
Modern molecular analyses of ceramic artifacts can provide unprecedented insights into the ancient past. If the full potential of this method is realized, it may be possible to determine the original contents of nearly any ceramic archaeological artifact recovered from underwater or terrestrial sites. This will allow new scientific questions to be posed regarding ancient agricultural production, as well as the preparation and preservation of food products and other organic material. Molecular analyses of archaeological artifacts will generate new knowledge of ancient contact networks, and the trade and economies of early civilizations. DNA evidence may allow scholars to discern the introduction of certain crops across regions and through time. Since some plants and crops can flourish only within limited water requirements and temperature constraints, these techniques may even provide data about ancient climate conditions.
WHOI Oceanus article
The southern portion of Chios island
is known as the 'mastichora'. It was the primary and perhaps sole source of high-quality mastic in the
ancient world, as first recorded by the Roman natural philosopher Pliny, circa 60 A.D. Modern scholars have
hypothesized that mastic resin preserved the famous Chian wines and provided their
distinctive flavor. If the resin in the unattributed amphora recoverd from the Chios-Oinousses wreck is indeed mastic, it is the first
direct suggestion for mastic cultivation in the Classical era. This would shift the
suspected origins of mastic production back in time at least 400 years. Because
the source of mastic was so highly localized in the southern part of Chios Island,
this suggests that this particular jar and by association the others in its
class were produced either on the island itself or at a site nearby. Similarly
to oregano, species in the Pistacia genus
have been experimentally demonstrated to possess strong antioxidant and
antimicrobial abilities, containing several different substances which prevent
oxidation processes and microbial activity. This could have facilitated
preservation of the jars' ancient contents, as well as the genetic material
within the amphora walls.