Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean

Simple item page
dc.contributor.advisorHeathfield, Laura
dc.contributor.advisorMartin, Donna-Lee
dc.contributor.authorMphaka, Francina Dimpho
dc.date.accessioned2026-01-13T07:12:17Z
dc.date.available2026-01-13T07:12:17Z
dc.date.issued2025
dc.date.updated2026-01-12T07:19:23Z
dc.description.abstractDeceased 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.
dc.identifier.apacitationMphaka, F. D. (2025). <i>Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean</i>. (). University of Cape Town ,Faculty of Health Sciences ,Department of Pathology. Retrieved from http://hdl.handle.net/11427/42539en_ZA
dc.identifier.chicagocitationMphaka, Francina Dimpho. <i>"Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean."</i> ., University of Cape Town ,Faculty of Health Sciences ,Department of Pathology, 2025. http://hdl.handle.net/11427/42539en_ZA
dc.identifier.citationMphaka, F.D. 2025. Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean. . University of Cape Town ,Faculty of Health Sciences ,Department of Pathology. http://hdl.handle.net/11427/42539en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Mphaka, Francina Dimpho AB - 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. DA - 2025 DB - OpenUCT DP - University of Cape Town KW - False Bay KW - Deceased KW - Human KW - DNA LK - https://open.uct.ac.za PB - University of Cape Town PY - 2025 T1 - Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean TI - Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean UR - http://hdl.handle.net/11427/42539 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/42539
dc.identifier.vancouvercitationMphaka FD. Evaluation of forensic DNA profiling success on teeth that have been submerged in the ocean. []. University of Cape Town ,Faculty of Health Sciences ,Department of Pathology, 2025 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/42539en_ZA
dc.language.isoen
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Pathology
dc.publisher.facultyFaculty of Health Sciences
dc.publisher.institutionUniversity of Cape Town
dc.subjectFalse Bay
dc.subjectDeceased
dc.subjectHuman
dc.subjectDNA
dc.titleEvaluation of forensic DNA profiling success on teeth that have been submerged in the ocean
dc.typeThesis / Dissertation
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMPhil
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_hsf_2025_mphaka francina dimpho.pdf
Size:
4.51 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.72 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Masters