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Technical Note: Lysis and purification methods for increased recovery of degraded DNA from touch deposit swabs

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Article number111102
JournalForensic Science International
Early online date12 Nov 2021
E-pub ahead of print12 Nov 2021
PublishedJan 2022

Bibliographical note

Funding Information: This work was supported by the Fulbright-King's College London Partnership Award. Funding Information: This work was supported by the Fulbright-King’s College London Partnership Award . Publisher Copyright: © 2021 The Authors

King's Authors


Touch deposits are a routine yet challenging sample type in forensic casework and research. Recent work investigating their contents has indicated corneocytes to be the major cellular constituent while cell-free DNA is present at significant levels. Prolonged incubation including a reducing agent such as DTT has been shown to lyse corneocytes; a plasma cfDNA recovery kit which targets shorter DNA fragments has been demonstrated to improve cfDNA recovery from hand rinses. Herein these methods are combined and tested on mock casework touch deposit swabs from communal surface areas. Both fluorescence- and qPCR-based quantification methods are used and their results compared to query DNA degradation levels. Both proposed lysis and purification methods demonstrate increased recovery of DNA detectable with fluorescence quantification and some additional alleles at short loci, indicating high levels of fragmented DNA in these samples

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