Thermal Effects on DNA Degradation in Blood and Seminal Stains: Forensic View

Abstract

Forensic investigations using DNA analysis have been grown rapidly. Samples retrieved from crime scene may be exposed to different conditions before proceeding. This study aimed to evaluate the effect of different grades of temperature and burn on DNA extraction and typing. Methods: Seven mL of blood and four mL of semen were collected from each volunteer. Effects of temperature grades (100 °C, 50 °C, 37 °C, 4 °C, −20 °C, and burn) on blood and seminal stain were tested. Results: Bloodstains exposed to temperature grades 100 °C, 50 °C, 37 °C, 4 °C, and −20 °C can be identified using preliminary test while burnt blood stain cannot. Seminal stains exposed to temperature grades 37 °C, 4 °C, and −20 °C can be identified by Florence test while those exposed to 100 °C, 50 °C, and burn cannot. Blood and seminal stains exposed to temperature grades 100 °C, 50 °C, and burn show marked reduction in DNA concentration while maximum DNA conc could be recovered from stains exposed to temperature grade temperature. Both blood and seminal DNA was affected only in case of burn without significant difference between THO1 and Amelogenin primers. Conclusion: High environmental temperature affect the quantity of extracted DNA from different stains but less effect on the quality of extracted DNA. Burn affects both preliminary test, DNA quantity, and quality in stains.

Assessment of Blood and Semen Detection and DNA Collection from Swabs up to Three Months after Deposition on Five Different Cloth Materials

“…The stability of bloodstains over time under different environmental conditions such as temperature and humidity has been analyzed by diverse methodologies and reported in the literature. Even though the decomposition process of blood once outside the body has been largely studied and distinguishable chemical compounds have been found and characterized between “recent” and “older” bloodstains [ 9 , 12 ], it has also been shown that nucleic acids such as DNA and different kinds of RNA remain stable and whole enough to be used for downstream analyses over time lapses as long as 30 days after deposition and exposition of the samples to harsh conditions such as elevated temperatures, high humidity, and laundry cycles [ 26 , 27 ].…”

The invisible witness: air and dust as DNA evidence of human occupancy in indoor premises

“…Dust is a reservoir of human skin cells and biological material, which can originate from current and past occupants of a specific location. DNA accumulated in dust can persist for a long time, from a few months up to a few years, depending on environmental factors such as light, heat, moisture, and cleaning agents, which may cause degradation 19 , 39 – 41 . On the other hand, DNA present in the air is more likely to represent individuals who recently occupied a room.…”

Amplification of vWA, FGA, and TH01 loci of DNA Samples Isolated From Ring Stored at Room Temperature

“…DNA degradation is also affected by hydrolytic attack on the base bonds of glycosidic sugars which can lead to base sites by depurination (26). The same mechanism can be followed by single and double-strand cleavage in an alkaline environment or by DNA-DNA cross-linking and DNA-protein in an acidic environment.…”