A B S T R A C TDenial of ownership of urine samples submitted by athletes for doping control has led to an increasing need to incorporate DNA analysis into testing protocols. As there are often large volumes of samples to process, a streamlined sample collection and analysis protocol suitable for urine samples that is quick, reliable, and economical would be highly advantageous. FTA ® cards have been employed extensively for preparing and preserving genetic material for long periods of time at room temperature. This study reports the possibility of using FTA ® cards to store urinary DNA, which can be used directly as templates in STR analysis for human identification. Urine samples from six male and female volunteers were collected. The sample preparation steps for harvesting cells from urine, such as minimum urine volume required and centrifugal speed, were optimised, and suitable sizes of the FTA ® card punches were determined. The results showed that regardless of the sample donor's sex, a complete DNA profile could be reproducibly generated from a single 2.0-mm punch of the 3-mL urine samples that had been deposited on FTA ® cards using the standard PCR conditions for AmpFLSTR ® Identifiler ® Plus. The developed protocol could become an integral part of a guideline for authentication of urine samples submitted for doping control or forensic toxicological analysis, where cost per sample and storage space are factors of consideration.
Poor storage of biological evidence on cotton swabs is known to lead to fungal and bacterial growth. However, there are often situations where it is inconvenient to dry the swabs without running the risk of contamination, or where only plastic bags are the best option for packaging material. This study aims to investigate the effectiveness of using 70% ethanol (v/v) and 100% isopropanol (v/v) to prevent or delay microbial growth on cotton swabs containing biological evidence and their effects on the subsequent STR analysis. The alcohols was applied on cotton swabs as moistening agent prior to collection of dried saliva stains. The cotton swabs were then packaged immediately in sealable plastic bags and stored at room temperature (27-29°C) for up to 5 days to simulate improper storage conditions. DNA was extracted and then amplified using AmpFLSTR ® Identifiler ® Plus PCR Amplification kit to obtain STR profiles. The results showed no observable fungal growth on any of the swabs moistened with 70% ethanol (v/v) or 100% isopropanol (v/v), and full STR profiles could be obtained from these swabs, while the growth was observed on swabs moistened with sterile deionised water after 5 days. The outcome of this study could be used to suggest an alternative DNA evidence collection and storage method in remote areas where samples must be transported in non-ideal conditions to central labs for analysis.
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