FACS separation of non-compromised forensically relevant biological mixtures

Timothy J Verdon; R John Mitchell; Weisan Chen; Kun Xiao; Roland A H van Oorschot

doi:10.1016/j.fsigen.2014.10.019

FACS separation of non-compromised forensically relevant biological mixtures

Forensic Sci Int Genet. 2015 Jan:14:194-200. doi: 10.1016/j.fsigen.2014.10.019. Epub 2014 Oct 31.

Authors

Timothy J Verdon¹, R John Mitchell², Weisan Chen³, Kun Xiao³, Roland A H van Oorschot⁴

Affiliations

¹ Office of the Chief Forensic Scientist, Victoria Police Forensic Services Centre, 31 Forensic Drive, Macleod 3085, VIC, Australia; Department of Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne 3086, VIC, Australia. Electronic address: timjverdon@gmail.com.
² Department of Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne 3086, VIC, Australia.
³ Department of Biochemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne 3086, VIC, Australia.
⁴ Office of the Chief Forensic Scientist, Victoria Police Forensic Services Centre, 31 Forensic Drive, Macleod 3085, VIC, Australia.

PMID: 25450793
DOI: 10.1016/j.fsigen.2014.10.019

Abstract

Although focusing attention on the statistical analysis of complex mixture profiles is important, the forensic science community will also benefit from directing research to improving the reduction of the incidence of mixtures before DNA extraction. This preliminary study analysed the use of fluorescence assisted cell sorting (FACS) for separation of cellular mixtures before DNA extraction, specifically mixtures of relatively fresh blood and saliva from two donors, prepared in 14 different mixture ratios. Improvements in the number of detectable alleles from the targeted cell type and overall profile quality were seen when compared to the results from unseparated samples. STRmix calculations revealed increases in likelihood ratios after separation, demonstrating the potential for higher probative values to be obtained from forensically relevant mixtures after subjecting them to FACS than from unsorted samples.

Keywords: Antibodies; Cell separation; DNA profile mixtures; Fluorescence assisted cell sorting; Forensic biology; Trace DNA.

MeSH terms

Cell Separation*
Flow Cytometry*
Forensic Genetics*