Tracking the origin of worked elephant ivory of a medieval chess piece from Belgium through analysis of ancient DNA

Abstract

The morphological identification of raw biological material used to produce archeological artifacts is sometimes difficult or even impossible. In recent years, newly developed biochemical techniques have allowed more reliable identification of exploited animal species, even for otherwise taxonomically undiagnostic fragments, and thus can help pinpoint the geographical origin of the raw material.However, in addition to being costly, these techniques involve destructive sampling. This explains why they are rarely applied to archeological artifacts, especially those made of precious, imported raw material or those representing intact works of art. Here, we analyzed the ancient DNA (aDNA) of a medieval chess piece made of ivory of unknown origin, recovered from a medieval settlement in Jambes (Namur), Belgium. This chess piece was broken during excavation. We took this unfortunate event as an opportunity to perform aDNA extraction, to try to answer three questions: (1) What Proboscidean species does the ivory come from?; (2) Can we establish the geographic origin of the ivory more precisely?; and (3) Does doing so help our understanding of (part of) the trade route followed by the ivory? We sequenced two short fragments of the mitochondrial genome and compared them with publicly available DNA data. This enabled the identification of the raw material as an African elephant (genus Loxodonta). Although the results cannot exclude that the ivory comes from a forest elephant, the recovered DNA sequence is currently found only among savanna elephant DNA records. The ivory likely originates from an eastern or southern African country and was therefore probably transported along the African trade route passing through the Swahili Corridor. However, the precise itinerary followed by this ivory from the African shore of the Mediterranean Sea to Europe, and then to the archeological site from which it was recovered, remains unknown. Such identification contributes to documenting past trade networks and long-distance exchange.

Species identification of ivory and bone museum objects using minimally invasive proteomics

“…The identification of elephant ivory using DNA analysis is becoming a vital tool in prosecutions relating to hunting and poaching, where methods typically require 200 mg of material ( 11 , 12 ). DNA analysis has also been used to identify the species of origin of museum objects, including an elephant ivory chess piece, and sperm whale teeth, where tens of milligrams of material were required to confidently identify the species of origin ( 13 , 14 ). Other nondestructive methods such as infrared and Raman spectroscopies are also used to classify species-specific features ( 15 , 16 ).…”