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Indirect DNA Transfer and Forensic Implications: A Literature Review
Francesco Sessa1, Cristoforo Pomara1, Massimiliano Esposito2
1Department of Medical, Surgical and Advanced Technologies "G.F. Ingrassia", University of Catania, 95121 Catania, Italy.
Genes
|December 23, 2023
Summary
Indirect DNA transfer, or secondary transfer, is a complex forensic challenge. Understanding factors like DNA amount, contact type, and source quality is crucial for accurate crime scene investigations.
Area of Science:
- Forensic Science
- Molecular Biology
- Genetics
Background:
- Advances in DNA profiling allow detection of minute DNA amounts (100 pg), enabling new defense strategies.
- Defense teams increasingly question DNA transfer mechanisms rather than the evidence itself.
Purpose of the Study:
- To review experimental studies on indirect DNA transfer.
- To analyze methods, sampling, extraction, and results of selected research on secondary DNA transfer.
Main Methods:
- Systematic literature review using Scopus and Web of Science databases.
- Analysis of 49 selected papers focusing on experimental design and findings related to indirect DNA transfer.
Main Results:
- Secondary DNA transfer is influenced by the amount of DNA shed, type and duration of contact, and DNA source quality.
- Individual characteristics and environmental conditions introduce variations and exceptions.
- Secondary transfer is a complex, dynamic phenomenon impacting forensic investigations.
Conclusions:
- Accurate detection and interpretation of secondary DNA transfer are vital to prevent misattribution of individuals to crime scenes.
- Developing standardized protocols and well-designed studies is necessary to enhance understanding and reliability of DNA evidence.
- Bayesian networks can aid in the correct interpretation of secondary transfer evidence.
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