The recovery of DNA in indoor and outdoor area environments



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After attending this presentation, attendees will have an understanding of how scientific techniques such as polymerase chain reaction (PCR) are used in detecting the presence of pig (Sus scrofa) DNA collected from intestines of maggots. The focus of the study is to analyze samples collected from the intestines of early in-star maggots used to identify the presence of pig (Sus scrofa) DNA in decomposed remains placed in an open air environment and in an enclosed environment. We hypothesize that the amount of DNA recovered will vary significantly between the two environments. This study, involves two female pigs that are being used as an animal model for human victims, suspects, or third party suspects for forensic investigations. Deoxyribonucleic acid sequence data was obtained from the intestines of maggots that fed on pig remains. Deoxyribonucleic acid has become standard in forensic science to analyze biological samples from decomposed remains. In addition, DNA serves as an essential tool for the identification of humans.
This presentation will affect the forensic community by identifying how environmental factors can influence postmortem changes and affect the presence of DNA on remains. In order to further explore the effects of indoor and outdoor areas the decomposition and insect colonization of pig carcasses were observed over a 14-day period in a semi-arid environment located at Research Site located in Lubbock, Texas. Two juvenile female pig carcasses weighing approximately 15 kg was placed at Site; one was placed inside a wooden house and the other placed outdoors in a field. Observations and sample collection from the pig carcasses were conducted daily. Blowfly (Calliphoridae) larvae (maggots) were collected in late summer and the intestines of the insects were analyzed to determine the amount of DNA present. The characteristics of a semi-arid environment are such that developmental growth of maggots may be impeded, consequently having a possible influence on the amount of DNA recovered. Maggots were collected and preserved in 15 mL falcon tubes filled with 5-10 mL of 70% ethanol. All larvae samples collected were be placed in a freezer at 40 C to improve preservation of the DNA in maggots and stored until ready for extraction. Following DNA extraction polymerase chain reaction assay was used to identify the presence of DNA recovered from the maggot’s intestines. This procedure identifies and purifies the DNA recovered from samples and can be used as evidence to solve criminal cases such as homicide, sexual assault, and negligence. Gene sequences were amplified by PCR, sequenced, and analyzed by capillary electrophoresis. The expected findings of this study determined that arid environments can affect the amount and recovery of DNA. Therefore, these results determined that environmental factors can show differences in decomposition patterns that can influence the recovery of DNA in remains.



Arid environment, Decomposition, Deoxyribonucleic acid (DNA), Forensic science, Polymerase chain reaction (PCR)