Time-Dependent Effects of Temperature and Humidity on Quality of DNA in samples of Human Saliva, Blood and Semen in Kuwait

Abstract

Forensic science is growing rapidly in the world today. During the past ten years, medico-legal investigations highly expanded to include all areas of forensic science. The present aim of project investigated 29 samples of blood and 29 samples of saliva swabs that were collected from human volunteers. The saliva samples were collected by buccal swab but the blood samples were collected by Bode Secur Swab S.I.T. Collector. The experiments were done at four different temperatures (55°C, 37°C, 24°C and 4°C) for 28 days. The results showed that, DNA quantity that was investigated at a temperature of 4°C and 24°C in both blood and saliva samples was more or less remained the same during the whole period of the study, comparing values for day one with all other days including day 28. DNA quantification of human blood following extraction at 37°C was 46.14 ng/μl ± 0.22 at day one then starts to decrease until it reached 36.05 ng/μl ± 0.07 at day 28. In contrast, the result obtained from real-time PCR showed that, when the temperature was raised to 55°C, the DNA started to degrade with time until it reaches zero at day 12. The results clearly show that DNA is extremely sensitive to heat. In conclusion, the present project has shown that accidental deaths are the major cause for un-natural deaths in Kuwait. Moreover, the study concluded that an environmental temperature of 55°C, revealed no DNA survival after 12 days of exposure.