Solving Cold Cases with Low-Quality DNA: Whole Genome Sequencing Explained #worldresearchawards

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Forensic Investigative Genetic Genealogy Based on Low-Quality DNA Whole Genome Sequencing Data

Organized by: International Forensic Scientist Awards
Website: forensicscientist.org

17th Edition of Forensic Scientist Awards 29-30 December 2025 | Dubai, United Arab

Introduction

Forensic science has entered a transformative era with the emergence of forensic investigative genetic genealogy (FIGG). This advanced approach has enabled investigators to identify unknown individuals and resolve long-standing cold cases by leveraging genetic relationships rather than relying solely on direct DNA matches. One of the most significant breakthroughs in recent years is the successful application of whole genome sequencing (WGS) to low-quality, degraded, or limited DNA samples, which were once considered unsuitable for forensic analysis.

This article explores how low-quality DNA whole genome sequencing data can be effectively used in forensic investigative genetic genealogy, highlighting technological advances, analytical challenges, and real-world applications.

What Is Forensic Investigative Genetic Genealogy (FIGG)?

Forensic investigative genetic genealogy combines forensic DNA profiling with genealogical database analysis to identify individuals through their biological relatives. Unlike traditional forensic methods that depend on short tandem repeats (STRs), FIGG primarily utilizes single nucleotide polymorphisms (SNPs) distributed across the genome.

By comparing SNP profiles to public or law-enforcement-approved genealogy databases, investigators can infer familial relationships and construct family trees, eventually narrowing down potential identities.

Challenges of Low-Quality DNA in Forensic Investigations

Low-quality DNA samples commonly arise from:

  • Aged or degraded biological material

  • Environmental exposure (heat, moisture, UV light)

  • Low-template or trace DNA samples

  • Skeletal remains or highly compromised tissues

Such samples often suffer from fragmentation, allelic dropout, contamination, and sequencing errors, making conventional forensic typing difficult or impossible.

Role of Whole Genome Sequencing (WGS)

Whole genome sequencing has revolutionized forensic genomics by enabling the analysis of millions of genetic markers, even from compromised samples. When applied to low-quality DNA, WGS offers several advantages:

  • Recovery of genome-wide SNP data from fragmented DNA

  • Improved kinship inference using low-coverage sequencing

  • Enhanced statistical power compared to STR-based methods

  • Compatibility with advanced bioinformatics correction models

Low-coverage WGS, when combined with probabilistic algorithms, can still generate reliable genetic profiles suitable for genealogical comparison.

Bioinformatics Strategies for Low-Quality DNA Data

The success of FIGG using degraded DNA relies heavily on bioinformatics pipelines, including:

  • Quality filtering and error correction

  • Imputation of missing genetic data

  • Contamination detection and removal

  • Statistical kinship analysis

These computational approaches allow researchers to maximize usable genetic information while minimizing false associations.

Applications in Forensic Casework

The integration of WGS-based FIGG has had a profound impact on forensic investigations, particularly in:

  • Cold case resolution

  • Identification of unidentified human remains

  • Historical and humanitarian investigations

  • Disaster victim identification

Numerous previously unsolved cases have been reopened and resolved using low-quality DNA samples that traditional methods failed to analyze.

Ethical, Legal, and Privacy Considerations

While FIGG offers immense investigative power, it raises important ethical and legal questions. Responsible use requires:

  • Compliance with legal frameworks and consent policies

  • Transparency in database usage

  • Protection of genetic privacy

  • Clear separation between forensic and recreational genetic data

Ethical oversight is essential to maintain public trust and ensure the appropriate application of this technology.

Future Directions

Ongoing advancements in sequencing chemistry, machine learning, and forensic bioinformatics continue to expand the limits of what is possible with low-quality DNA. As methods improve, forensic investigative genetic genealogy is expected to become more accurate, accessible, and standardized across jurisdictions.

Conclusion

Forensic investigative genetic genealogy based on low-quality DNA whole genome sequencing data represents a powerful evolution in forensic science. By combining cutting-edge genomics with genealogical analysis, investigators can now extract meaningful information from even the most compromised samples—opening new pathways for justice, identification, and closure.

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