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Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs
The burden of unresolved crime in South Africa highlights the need to improve methods of identifying perpetrators of crimes. One globally accepted method for human identification is forensic DNA profiling. Since trace evidence is often retrieved in small amounts, the optimal recovery of DNA from the...
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| Format: | Thesis |
| Language: | English |
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Division of Forensic Medicine and Toxicology
2021
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| _version_ | 1867614422500900864 |
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| access_status_str | Open Access |
| author | Hitewa, Alina Ndahafa |
| author2 | Heathfield, Laura |
| author_browse | Heathfield, Laura Hitewa, Alina Ndahafa |
| author_facet | Heathfield, Laura Hitewa, Alina Ndahafa |
| author_sort | Hitewa, Alina Ndahafa |
| collection | Thesis |
| description | The burden of unresolved crime in South Africa highlights the need to improve methods of identifying perpetrators of crimes. One globally accepted method for human identification is forensic DNA profiling. Since trace evidence is often retrieved in small amounts, the optimal recovery of DNA from these samples is crucial. Methods for the recovery of touch DNA from swabs typically make use of a spin basket or filter, combined with a centrifugation step, to enhance the release of cells from the swab prior to DNA extraction. The NucleoSpin® Forensic Filter (Macherey-Nagel, Düren) is one such example, but it has not been thoroughly assessed on touch DNA samples. This study aimed to assess if the inclusion of the NucleoSpin® Forensic Filter significantly improved DNA recovery and DNA profiling success from cotton and flocked swabs used to collect touch DNA and buccal cells (control). Buccal cells and touch DNA samples were collected from 25 volunteers using each swab type (cotton and flocked) in duplicate. DNA was extracted from the samples using the NucleoSpin® DNA Forensic kit, one set with, and the other set without, NucleoSpin® Forensic Filters. DNA concentration was assessed using Qubit™ fluorometry and qPCR, and DNA profiling was done using the PowerPlex® ESX 16 system. The inclusion of the NucleoSpin® Forensic Filters significantly improved DNA concentration in buccal cells collected using flocked swabs (p = 0.035). However, no significant differences were noted for touch DNA samples, for either swab type. There was also no significant difference in DNA profiling success when NucleoSpin® Forensic Filters were used, regardless of swab and sample type. These results suggest that the NucleoSpin® Forensic Filters should not be included in the DNA extraction workflow, particularly for touch DNA samples. With only 16 % of touch DNA samples yielding full DNA profiles, there is the need to improve DNA recovery. Factors such as swab type and swab preservation buffers, should be investigated in future research. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/33810 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:51:47.689Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Division of Forensic Medicine and Toxicology |
| publisherStr | Division of Forensic Medicine and Toxicology |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/33810 Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs Hitewa, Alina Ndahafa Heathfield, Laura Gibbon, Andrea Mole, Calvin Biomedical Forensic Science The burden of unresolved crime in South Africa highlights the need to improve methods of identifying perpetrators of crimes. One globally accepted method for human identification is forensic DNA profiling. Since trace evidence is often retrieved in small amounts, the optimal recovery of DNA from these samples is crucial. Methods for the recovery of touch DNA from swabs typically make use of a spin basket or filter, combined with a centrifugation step, to enhance the release of cells from the swab prior to DNA extraction. The NucleoSpin® Forensic Filter (Macherey-Nagel, Düren) is one such example, but it has not been thoroughly assessed on touch DNA samples. This study aimed to assess if the inclusion of the NucleoSpin® Forensic Filter significantly improved DNA recovery and DNA profiling success from cotton and flocked swabs used to collect touch DNA and buccal cells (control). Buccal cells and touch DNA samples were collected from 25 volunteers using each swab type (cotton and flocked) in duplicate. DNA was extracted from the samples using the NucleoSpin® DNA Forensic kit, one set with, and the other set without, NucleoSpin® Forensic Filters. DNA concentration was assessed using Qubit™ fluorometry and qPCR, and DNA profiling was done using the PowerPlex® ESX 16 system. The inclusion of the NucleoSpin® Forensic Filters significantly improved DNA concentration in buccal cells collected using flocked swabs (p = 0.035). However, no significant differences were noted for touch DNA samples, for either swab type. There was also no significant difference in DNA profiling success when NucleoSpin® Forensic Filters were used, regardless of swab and sample type. These results suggest that the NucleoSpin® Forensic Filters should not be included in the DNA extraction workflow, particularly for touch DNA samples. With only 16 % of touch DNA samples yielding full DNA profiles, there is the need to improve DNA recovery. Factors such as swab type and swab preservation buffers, should be investigated in future research. 2021-08-24T01:25:54Z 2021-08-24T01:25:54Z 2021 2021-08-23T23:51:12Z Master Thesis Masters MPhil http://hdl.handle.net/11427/33810 eng application/pdf Division of Forensic Medicine and Toxicology Faculty of Health Sciences |
| spellingShingle | Biomedical Forensic Science Hitewa, Alina Ndahafa Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs |
| thesis_degree_str | Master's |
| title | Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs |
| title_full | Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs |
| title_fullStr | Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs |
| title_full_unstemmed | Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs |
| title_short | Investigating the effect of NucleoSpin® Forensic Filters on DNA recovery from swabs |
| title_sort | investigating the effect of nucleospin r forensic filters on dna recovery from swabs |
| topic | Biomedical Forensic Science |
| url | http://hdl.handle.net/11427/33810 |
| work_keys_str_mv | AT hitewaalinandahafa investigatingtheeffectofnucleospinforensicfiltersondnarecoveryfromswabs |