Dandruff as a Forensic Biomarker: A Novel Approach in Trace Evidence Analysis

Abstract

The forensic application of mitochondrial DNA (mtDNA) recovered from dandruff sampled using different methods, such as nail clippings, combs, hairbrushes, pillowcases, and clothes, is investigated here. Though sometimes neglected in forensic investigations, dandruff holds nucleated cells that contain useful genetic information. This paper seeks to develop a successful and effective means of recovering mtDNA from dandruff, particularly in instances where traditional sources of DNA are not available or are deteriorated.Dandruff samples were also obtained from volunteers by employing a variety of non-invasive approaches: nail clippings accompanied by attached dandruff, hairbrushes, combs, pillowcase, and apparel. mtDNA was isolated through a commercial kit for DNA isolation, and detection was done with the help of gel electrophoresis. For confirmation of accuracy and reliability of the extracted DNA, quantitative analysis was carried out to determine DNA yield, while Polymerase Chain Reaction (PCR) amplification and sequencing was carried out to check mtDNA quality and purity. The results confirmed successful mtDNA extraction, where high-quality sequences were applicable for forensic use.The study confirms that dandruff is a suitable and easily accessible source of DNA for forensic analysis. Its ability to be easily collected from personal items without contact makes it particularly useful in circumstances where traditional DNA samples are unavailable. The method can be applied to aid crime scene investigations, suspect identification, cold case solution, mass disaster victim identification, and DNA degradation research.Also to be considered are ethical concerns surrounding consent and privacy, as dandruff naturally flakes off and can be sampled without the knowledge of the individual. The current study presents dandruff as a significant and useful forensic source of DNA and calls for future research that would allow the implementation of this method in forensic analysis.

Introduction

Overview:
Mitochondria are abundant cell organelles known primarily for energy production but also play crucial roles in forensic science and genetics. Mitochondrial DNA (mtDNA) is a small, circular genome with 37 genes and is maternally inherited. It is highly useful in forensic identification, especially for degraded samples, mass disaster victim identification, and cases involving maternal lineage, as it is more abundant and resistant to degradation than nuclear DNA (nDNA). Traditional DNA sources like blood and saliva are common in forensics, but dandruff, a flaky scalp skin, is emerging as a non-invasive, easily accessible DNA source with a higher DNA yield and stability.

Mitochondria:
Mitochondria generate energy and regulate key cellular functions. They contain many copies of mtDNA per cell, which is maternally inherited, does not recombine, and has a high mutation rate. These features make mtDNA valuable in forensic science for identifying degraded samples, exonerating wrongful convictions, and studying historical or archaeological remains.

Mitochondrial DNA vs Nuclear DNA:

• Location: mtDNA is circular and found in mitochondria; nDNA is linear and housed in the nucleus.

• Inheritance: mtDNA is maternally inherited without recombination; nDNA is inherited from both parents with recombination.

• Function: mtDNA encodes genes mainly for energy metabolism; nDNA codes for a wide variety of cellular functions.

• Genetics: mtDNA mutates faster and lacks histone packaging unlike nDNA.

Dandruff as a DNA Source:
Dandruff is caused by overgrowth of Malassezia fungus and skin shedding. It offers advantages in forensics due to its non-invasive collection, stability, and higher DNA content compared to conventional samples. Despite limited specialized extraction methods, kit-based approaches show promising results.

DNA Evidence Sources:
Common forensic DNA sources include blood, saliva, semen, urine, and biological swabs, each varying in DNA quantity and ease of collection. Dandruff is a novel, less invasive source with potential for forensic applications.

DNA Extraction from Keratinized Tissues:
Keratin-rich samples like hair, nails, and dandruff require chemical digestion (e.g., with DTT and proteinase K) followed by organic extraction or kit-based protocols for DNA isolation.

DNA Quality and Quantity Assessment:
Ensuring DNA integrity and purity is crucial for analysis. Techniques include gel electrophoresis (for integrity) and spectrophotometry (for purity, using absorbance ratios at 260/280 nm).

Conclusion

The mitochondria is present in cell in abundant amount, as we know that the function of mitochondria is to provide energy to cell for biological activities, however there are more than that. In aspect of Forensic Science, Genetics the mitochondria has significant role here. If we trace back very far to the beginning of mitochondria researches have established that the mitochondria was a bacterial cell engulfed by the eukaryotic cell but wasn\'t digested and the symbiotic relationship began there. The human mitochondrial DNA (mtDNA) is a 16?569 bp double-stranded circular molecule and includes 37 genes encoding two rRNAs, 22 tRNAs and 13 polypeptides.Human mitochondrial DNA has many uses i.e. missing person identity, war or disaster victim identification, maternal inheritance cases, government databases etc. In comparison to nuclear DNA(nDNA) mitochondrial DNA(mtDNA) is present in abundant amount however that’s not only benefit but mtDNA can sustain in harsh environment conditions also for sample which are exposed for too long can also be useful for mtDNA analysis unlike nDNA which degraded gradually as passage of time.

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Copyright © 2025 Sandhya Pandya. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.