Effect of Storage on the Quantity and Quality of DNA Isolated from Preserved and Discarded Blood: Forensic Applications

Background and Objective: The preservation of DNA is of eclectic attention to scientists in different fields of studies. The target of this study was to investigate if storage has any effect on the quantity and quality of DNA isolated from blood. Materials and Methods: A total of ten patients were used for the study and 20 blood samples were collected and fashioned into two precise categories, freshly preserved and carelessly discarded blood samples. Each of the categories contained 4 females and 6 males. The preserved and discarded groups were kept in the EDTA bottle at 4°C and in the syringe kept in dump site, respectively. DNA was extracted using phenol-chloroform method while the concentration and quality of DNA was measured spectrophotometrically and electrophoretically, respectively. Results: The concentrations of DNA in the preserved blood samples showed a significant increase compared to discarded samples, t (18) = 5.96, p = 0.00. Also, there was a significant increase in the quality of DNA obtained from the preserved blood samples when compared to the discarded groups, t (18) = 9.97, p = 0.00. Results of gel electrophoresis indicated that DNA from preserved blood was more intact and most probably had higher molecular weight and less shearing than the DNA compared to discarded blood. Conclusion: The results of the study showed that preservation has serious effects on the quantity and quality of DNA extracted. However, both samples are good for forensic investigations and molecular diagnosis of genetic diseases but preserved is better of.