Assessing the Risk of Secondary Transfer Via Fingerprint Brush Contamination Using Enhanced Sensitivity DNA Analysis Methods

J Forensic Sci. 2016 Jan;61(1):204-11. doi: 10.1111/1556-4029.12911. Epub 2015 Aug 24.

Abstract

Experiments were performed to determine the extent of cross-contamination of DNA resulting from secondary transfer due to fingerprint brushes used on multiple items of evidence. Analysis of both standard and low copy number (LCN) STR was performed. Two different procedures were used to enhance sensitivity, post-PCR cleanup and increased cycle number. Under standard STR typing procedures, some additional alleles were produced that were not present in the controls or blanks; however, there was insufficient data to include the contaminant donor as a contributor. Inclusion of the contaminant donor did occur for one sample using post-PCR cleanup. Detection of the contaminant donor occurred for every replicate of the 31 cycle amplifications; however, using LCN interpretation recommendations for consensus profiles, only one sample would include the contaminant donor. Our results indicate that detection of secondary transfer of DNA can occur through fingerprint brush contamination and is enhanced using LCN-DNA methods.

Keywords: DNA typing; fingerprint brush contamination; forensic science; low copy number; post-PCR cleanup; secondary transfer.

MeSH terms

  • DNA / genetics*
  • DNA / isolation & purification
  • DNA Fingerprinting*
  • Dermatoglyphics*
  • Equipment Contamination*
  • Forensic Medicine / instrumentation*
  • Humans
  • Microsatellite Repeats
  • Polymerase Chain Reaction

Substances

  • DNA