M.A. Theses: Alice Ann Storey, 2004
SAVE ME A DRUMSTICK: Molecular Taphonomy, Differential Preservation and Ancient DNA from the Kingdom of Tonga
This project was focused on the extraction and amplification of DNA from ancient samples of chicken (Gallus gallus) and sea turtle recovered from the Kingdom of Tonga. Results of this project demonstrate that small amounts of highly degraded ancient DNA template material is preserved in archaeological chicken remains. Two of the twelve samples tested yielded positively amplified DNA. The chicken D-loop sequences recovered are from the Plainware Phase of prehistory dating from approximately 2650 BP. However, the sporadic nature of the results suggest it is at the borderline of what can be done with contemporary techniques. Analysis of sequenced domesticated chicken remains from Tonga display an affinity with Chinese stocks identified as ‘isolates’ and may lend support to theories of a Southeast Asian origin.
This preliminary study provides evidence that chicken from Oceanic 'open air' sites may provide a parallel line of evidence to studies of other domesticates and human mtDNA to reconstruct migration and interaction in prehistoric Oceania. Further refinement of these methods, such as optimization of PCR protocols and quantification of PCR products make this a potential source of secondary evidence for future study.
In order to further understand preservational differences between sea turtle and chicken bone samples a secondary measure to assess preservation was sought. Collagen was selected because research suggested a similar structure and vulnerability to processes of degradation as DNA. The measurement of "collagen" yields indicates that this protein may also preferentially preserve in bird remains of some antiquity, but does not preserve in sea turtle or rat.
Several preliminary attempts, by other authors, to amplify aDNA from 'marginal' environments has suggested that DNA and collagen might not preserve well in hot and humid locales, particularly the tropics. It appears, however, that the unique structure of avian bones makes them more resistant to processes of diagenesis and enhances the preservation potential of aDNA and collagen. In Tonga (and the rest of Oceania) the association of these remains with midden deposits on the sea shore, also creates an environment in which DNA and collagen may bind to the minerals in sea sand conferring higher preservation potential.