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

TY - JOUR

T1 - Technical Note

T2 - Lysis and purification methods for increased recovery of degraded DNA from touch deposit swabs

AU - Burrill, Julia

AU - Daniel, Barbara

AU - Frascione, Nunzianda

N1 - 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

PY - 2022/1

Y1 - 2022/1

N2 - 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

AB - 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

KW - cfDNA

KW - Degraded DNA

KW - Lysis

KW - Mock casework swabs

KW - Touch deposit

KW - Touch DNA

KW - Trace DNA

UR - http://www.scopus.com/inward/record.url?scp=85119450935&partnerID=8YFLogxK

U2 - 10.1016/j.forsciint.2021.111102

DO - 10.1016/j.forsciint.2021.111102

M3 - Article

AN - SCOPUS:85119450935

SN - 0379-0738

VL - 330

JO - Forensic Science International

JF - Forensic Science International

M1 - 111102

ER -