The studies described here introduce a model for residue preservation on stone
tools. They simulate stone tool manufacture in order to define parameters important
for the study of DNA residues. Microscopic examination of stone tools has identified
microcracks that trap DNA and protein from animal blood cells. Thorough
investigation of different methods to recover residues from stone tools shows that
surface washing leaves DNA and protein, trapped in subsurface microcracks.
However, other extraction techniques are able to release 60-80% of DNA and protein
residues.
Previous research documents the identification of protein from stone tools
sonicated in 5% ammonium hydroxide, but it remains untested whether the same
treatment yields useable DNA. Using this treatment, I identified 13-year-old DNA
residues from experimentally manufactured stone tools. In addition, results clearly
indicate that washing procedures typically used to curate stone tools removed only a
small fraction of the DNA deposited during animal butchery.
Twenty-four pieces of chipped stone recovered from the Bugas-Holding site
were studied to explore the validity of ancient DNA residue identifications. Nine tools
yielded DNA residues. Modern humans did not touch three of these tools, which
suggests that the DNA recovered from them was present prior to excavation. One
tool, which was handled by excavators without gloves, harbored DNA from three
species, and these templates competed during PCR. On at least two tools, handling
after excavation introduced animal DNA unrelated to tool use. Careful testing of
Bugas-Holding chipped stone suggests that stone tools may harbor both ancient and
modern DNA, and that investigators must take great care to exclude modern DNA
from ancient specimens.
Ultimately, I developed and streamlined a method to analyze DNA-containing
residues preserved on stone tools. This led to several technical improvements in
ancient DNA residue analysis. These include a more effective DNA recovery
protocol, methods to measure sensitivity and inhibition of PCR in each sample, and
strategies to surmount competition between templates during amplification, which can
occur in samples that contain DNA from multiple species. These new developments
will help future investigators achieve the full potential of ancient DNA residue
analysis. / Graduation date: 2003
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32480 |
| Date | 28 February 2003 |
| Creators | Shanks, Orin C. |
| Contributors | Ream, Lloyd W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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