DNA extraction and quantification from human saliva deposited on fruits with human bite

Shahid Nazir, Muhammad Wasim, Muhammad Yasir Zahoor, Faiza Masood, Arman Khan, Ahmed Fayyaz, Allah Rakha


Background: Among important aspects of forensic science there stand recovery, preservation and analysis of stains originated by body fluid. DNA Isolated from evidence stains help to exclude an innocent suspect or to identify a perpetrator upon PCR-based typing. This study reports extraction and quantification of DNA from human saliva deposited on fruits. The research work was conducted at Department of Forensic Sciences, University of Health Sciences, Lahore and WTO laboratory of University of Veterinary and Animal Sciences, Lahore.

Methodology: DNA from saliva deposited on bitten fruits. DNA from 55 samples were extracted by Chelax method, Quantifiler® DNA Quantification Kit was used for quantification of the extracted samples and amplification of DNA was done in 7500 Real-Time PCR systems (Applied Biosystems, Foster City, CA). Total 55 samples including controls (positive and negative controls) were collected from bitten fruits by sterile swabs.

Results: All sample swabs with human saliva showed result for quantification. Overall good yield of DNA quantification obtained from all fruits and no sample showed internal inhibition. No sample showed non informative or incomplete quantification which occurs due to LCN (Low copy number) or lesser quantity of DNA extracted from saliva swab.

Conclusion: This study has provided with optimized protocol to isolate DNA from saliva found in very minute quantity on organic surfaces like fruits. Adaptation of this method can play a vital role in establishing new trends in human forensics practiced in Pakistan. Moreover, for future work in human forensics, this study can provide important practical basis.

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