A preliminary study on detecting human DNA in aquatic environments: Potential of eDNA in forensics

Area of Science:

• Forensic Science
• Environmental DNA (eDNA) Analysis
• Molecular Biology

Background:

• Human environmental DNA (eDNA) applications are underutilized in forensics.
• eDNA offers potential for detecting human presence in aquatic crime scenes.
• Factors influencing eDNA detectability and stability require investigation.

Purpose of the Study:

• To assess the detection and degradation rates of human eDNA in aquatic environments.
• To evaluate the recovery of nuclear short tandem repeat (STR) profiles and mitochondrial DNA (mtDNA) sequencing from human eDNA.
• To determine the stability and detectability of human eDNA in both freshwater and saltwater samples.

Main Methods:

• Spiking whole human blood into freshwater and saltwater samples.
• Filtering water samples using a 5 µm pore size filter.
• Collecting samples over 23 days and analyzing for human eDNA using qPCR and STR/mtDNA profiling.

Main Results:

• Human eDNA was detectable up to 36 hours in freshwater and 84 hours in saltwater.
• Limit of detection (LOD) for human eDNA was 205 copies/µl.
• Partial STR profiles were recovered up to 24 hours; full mtDNA profiles up to 48 hours (freshwater) and 72 hours (saltwater).

Conclusions:

• Human eDNA analysis is a valuable, complementary tool for forensic investigations in aquatic environments.
• Findings support the integration of eDNA techniques to enhance forensic capabilities and case resolution.
• Further research is recommended to optimize eDNA methods for forensic applications.