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Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean
Deceased humans that are recovered from marine environments contribute to the burden of unidentified bodies, both globally and in South Africa. Compromised conditions of these bodies make identification difficult. In these instances, DNA analysis becomes an invaluable tool for identification. Noneth...
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| Format: | Thesis |
| Language: | English English |
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Department of Pathology
2026
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| _version_ | 1867613239257333760 |
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| access_status_str | Open Access |
| author | Mphaka, Francina Dimpho |
| author2 | Heathfield, Laura |
| author_browse | Heathfield, Laura Mphaka, Francina Dimpho |
| author_facet | Heathfield, Laura Mphaka, Francina Dimpho |
| author_sort | Mphaka, Francina Dimpho |
| collection | Thesis |
| description | Deceased humans that are recovered from marine environments contribute to the burden of unidentified bodies, both globally and in South Africa. Compromised conditions of these bodies make identification difficult. In these instances, DNA analysis becomes an invaluable tool for identification. Nonetheless, there is a notable gap in existing literature regarding the use of DNA from teeth for identifying human remains recovered from marine environments. This study therefore aimed to evaluate forensic DNA profiling success on human teeth samples (n = 90) that were submerged in two different marine locations along Cape Town's coastline. Thirty adult volunteers each donated three wisdom teeth, where each tooth per individual was subjected to a different condition for 20 days: one was submerged in False Bay, one was submerged in Table Bay and the remaining tooth was kept as an unsubmerged, matched control in the laboratory. DNA was extracted and quantified using quantitative polymerase chain reaction before undergoing DNA profiling. No significant difference was observed in the likelihood ratio between DNA recovered from samples submerged in Table Bay (median: 1.031 × 1013; range: 4.221 to 5.633 × 1031) compared to False Bay (median: 3.501 × 1015 range: 1.557 × 103 to 2.578 × 1035). As expected, matched control samples yielded significantly higher DNA concentrations than submerged samples and showed significantly higher Likelihood ratios (median: 3.094 × 1028; range: 11.11 to 1.614 × 1033) than submerged samples (p < 0.001). Three DNA profiles from False Bay samples showed no allele detection and therefore were uninformative. Further, allele drop-ins were observed in three DNA profiles from False Bay samples but none in Table Bay samples. These were hypothesised to be due to the presence of marine microbial DNA and could potentially confound DNA interpretations. Overall, the results suggested that the protocol used was suitable for DNA profiling of teeth samples recovered from Table Bay and further research is required to obtain insight into aquatic conditions affecting samples submerged in False Bay. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/42539 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:32:58.612Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Department of Pathology |
| publisherStr | Department of Pathology |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/42539 Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean Mphaka, Francina Dimpho Heathfield, Laura Martin, Donna-Lee False Bay Deceased Human DNA Deceased humans that are recovered from marine environments contribute to the burden of unidentified bodies, both globally and in South Africa. Compromised conditions of these bodies make identification difficult. In these instances, DNA analysis becomes an invaluable tool for identification. Nonetheless, there is a notable gap in existing literature regarding the use of DNA from teeth for identifying human remains recovered from marine environments. This study therefore aimed to evaluate forensic DNA profiling success on human teeth samples (n = 90) that were submerged in two different marine locations along Cape Town's coastline. Thirty adult volunteers each donated three wisdom teeth, where each tooth per individual was subjected to a different condition for 20 days: one was submerged in False Bay, one was submerged in Table Bay and the remaining tooth was kept as an unsubmerged, matched control in the laboratory. DNA was extracted and quantified using quantitative polymerase chain reaction before undergoing DNA profiling. No significant difference was observed in the likelihood ratio between DNA recovered from samples submerged in Table Bay (median: 1.031 × 1013; range: 4.221 to 5.633 × 1031) compared to False Bay (median: 3.501 × 1015 range: 1.557 × 103 to 2.578 × 1035). As expected, matched control samples yielded significantly higher DNA concentrations than submerged samples and showed significantly higher Likelihood ratios (median: 3.094 × 1028; range: 11.11 to 1.614 × 1033) than submerged samples (p < 0.001). Three DNA profiles from False Bay samples showed no allele detection and therefore were uninformative. Further, allele drop-ins were observed in three DNA profiles from False Bay samples but none in Table Bay samples. These were hypothesised to be due to the presence of marine microbial DNA and could potentially confound DNA interpretations. Overall, the results suggested that the protocol used was suitable for DNA profiling of teeth samples recovered from Table Bay and further research is required to obtain insight into aquatic conditions affecting samples submerged in False Bay. 2026-01-13T07:12:17Z 2026-01-13T07:12:17Z 2025 2026-01-12T07:19:23Z Thesis / Dissertation Masters MPhil http://hdl.handle.net/11427/42539 en eng application/pdf Department of Pathology Faculty of Health Sciences University of Cape Town |
| spellingShingle | False Bay Deceased Human DNA Mphaka, Francina Dimpho Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean |
| thesis_degree_str | Master's |
| title | Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean |
| title_full | Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean |
| title_fullStr | Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean |
| title_full_unstemmed | Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean |
| title_short | Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean |
| title_sort | evaluation of forensic dna profiling success on teeth that have been submerged in the ocean |
| topic | False Bay Deceased Human DNA |
| url | http://hdl.handle.net/11427/42539 |
| work_keys_str_mv | AT mphakafrancinadimpho evaluationofforensicdnaprofilingsuccessonteeththathavebeensubmergedintheocean |