title: Evaluation of samples comprising minute amounts of DNA.
abstract: Minute amounts of DNA representing only few diploid cells, may be interrogated using enhanced DNA profiling, which will be accompanied by stochastic amplification effects. Notwithstanding, a weight of evidence statistic may be calculated using current interpretation software. In this study, we profiled single donor, two- and three-person samples having only 3 pg to 12 pg of DNA per contributor using both standard and enhanced capillary electrophoresis (CE) injection settings. Likelihood ratios (LRs) were computed using LRmix Studio, compared for both types of profiles and examined in relation to the amount of DNA, drop-out level, number of detected alleles, peak heights and reproducibility of alleles. Especially for DNA profiles that were generated using enhanced CE, the obtained LRs could indicate strong evidence in favour of the prosecution (log10(LR)>6), also when the amount of DNA represented about half of a diploid cell equivalent in the amplification. These results illustrate that an assessment of the criminalistic relevance of a sample carrying minute amounts of DNA is essential prior to applying enhanced interrogation techniques and/or calculating a weight of evidence statistic.
authors.affiliation: Department of Human Biological Traces, Netherlands Forensic Institute, P.O. Box 24044, 2490 AA The Hague, The Netherlands. Electronic address: c.benschop@nfi.minvenj.nl.
authors.forename: Corina C G
authors.initials: CC
authors.lastname: Benschop
authors.affiliation: Department of Human Biological Traces, Netherlands Forensic Institute, P.O. Box 24044, 2490 AA The Hague, The Netherlands. Electronic address: h.haned@nfi.minvenj.nl.
authors.forename: Hinda
authors.initials: H
authors.lastname: Haned
authors.affiliation: Department of Human Biological Traces, Netherlands Forensic Institute, P.O. Box 24044, 2490 AA The Hague, The Netherlands. Electronic address: seongyeon@korea.kr.
authors.forename: Seong Yeon
authors.initials: SY
authors.lastname: Yoo
authors.affiliation: Department of Human Biological Traces, Netherlands Forensic Institute, P.O. Box 24044, 2490 AA The Hague, The Netherlands. Electronic address: t.sijen@nfi.minvenj.nl.
authors.forename: Titia
authors.initials: T
authors.lastname: Sijen
mesh_terms: D004247:DNA / Q000032:analysis* / Q000235:genetics; D016172:DNA Fingerprinting / Q000379:methods*; D005787:Gene Frequency; D006801:Humans; D016013:Likelihood Functions; D018895:Microsatellite Repeats
chemical_list: D004247:DNA
keywords: Enhanced profiling; Forensic science; Likelihood ratios; Low template DNA; Relevance of the evidence; Trace DNA