Massively parallel sequencing and STR analysis from partial bloody fingerprints enhanced with columnar thin films

Abstract

Fingerprint enhancement often includes either physical or chemical approaches, such as fingerprint powder or cyanoacrylate fuming, to improve the quality of a fingerprint for visualization and analysis. However, these methods become more complex when fingerprints are partial bloody, and these procedures may interfere with downstream DNA analysis. Columnar thin film (CTF) deposition is a type of nanotechnology that utilizes an evaporant material to enhance a fingerprint under low-pressure conditions. Short tandem repeat (STR) analysis is the traditional method employed in crime laboratories. When DNA is of poor quality and quantity, like that often obtained from fingerprints, little to no genetic information may be obtained. Single nucleotide polymorphisms (SNPs) may be used to glean additional information when STR analysis fails. In this pilot study, 100 partial bloody fingerprints were collected from two donors and deposited on five different crime scene substrates, in which half were enhanced with CTFs and were graded for quality by an IAI-certified latent fingerprint examiner. CTF-developed fingerprints, on average, had higher grades compared to non-developed partial bloody fingerprints. STR analysis using Fusion 6C was performed to assess inhibition from the evaporant materials, in which no inhibition was observed. Sequencing of SNPs using the Precision ID Identity Panel was also employed, in which genetic information that could not be obtained from STRs was acquired with SNPs. Various sample types (i.e. pristine, low quality, and contaminated) utilized in this project demonstrated the acceptable performance of the Precision ID Identity Panel.