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- All Subjects: Forensic Science
- All Subjects: blow flies
- Creators: Kobojek, Kimberly
- Creators: Parrott, Jonathan
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Despite the consistent coverage of death on a large scale, the average person is not often exposed to death on a personal level in this day and age. The deaths we see on television or in the movies are not typically connected to people with whom we are attached and so we are not required to work through our emotional response and experience. We are afforded the space to be a casual observer in most of the deaths that we see—we do not need the emotional and mental tools to cope with death on a personal level. While this distance from death may be true of the American whole, it is not entirely generalizable. Professionals in select fields are required to deal with death on a much more regular basis than the average person, including, but not limited to, healthcare and forensic professionals. In these professions, death is a fundamental aspect of the job—either as an expected risk or a necessary precursor. These professionals deal intimately with death, its causes, and its effects on a regular basis because of their chose line of work and, in doing so, are regularly exposed to death and other trauma which has the potential to affect them on both a professional and personal level. In doing so, these professionals are required to, as scientists, analyze and record these experiences with death through the lens of objectivity. These professionals are expected to maintain a professional distance while also being required to give an empathetic response to other’s trauma. The potential effect of this secondary trauma on these professionals is only sharpened by the culture of machismo in these science-based fields that prevents many professionals from expressing emotions regarding their job and getting the social support they need from others within their community.
Medicolegal forensic entomology is the study of insects to aid with legal investigations (Gemmellaro, 2017). Insect evidence can be used to provide information such as the post-mortem interval (PMI). Blow flies are especially useful as these insects are primary colonizers, quickly arriving at a corpse (Malainey & Anderson, 2020). The age of blow flies found at a scene is used to calculate the PMI. Blow fly age can be estimated using weather data as these insects are poikilothermic (Okpara, 2018). Morphological analysis also can be used to estimate age; however, it is more difficult with pupal samples as the pupae exterior does not change significantly as development progresses (Bala & Sharma, 2016). Gene regulation analysis can estimate the age of samples. MicroRNAs are short noncoding RNA that regulate gene expression (Cannell et al., 2008). Here, we aim to catalog miRNAs expressed during the development of three forensically relevant blow fly species preserved in several storage conditions. Results demonstrated that various miRNA sequences were differentially expressed across pupation. Expression of miR92b increased during mid pupation, aga-miR-92b expression increased during early pupation, and bantam, miR957, and dana-bantam-RA expression increased during late pupation. These results suggest that microRNA can be used to estimate the age of pupal samples as miRNA expression changes throughout pupation. Future work could develop a statistical model to accurately determine age using miRNA expression patterns.
In this experiment, the viability of gunshot residue (GSR) was examined. This was done through the very rarely researched intersection of forensic firearms analysis and forensic entomology. The question being resolved is if GSR can reliably be detected from secondary evidence transfer of GSR laden carrion onto flies and their larvae. While it is know that secondary and tertiary GSR evidence can be transferred by way of handshakes, no such research has been conducted on flies or their pupae. Findings indicated varying levels of detection of GSR on evidence. GSR could reliably be detected on fly bodies and their legs, but not on their pupae. This research is significant as it provides previously unknown information on this line of research and provides the groundwork for further research on this topic in the future.
Since the inception of what is now known as the Behavioral Analysis Unit (BAU) at the Federal Bureau of Investigation (FBI) in the 1970s, criminal profiling has become an increasingly prevalent entity in both forensic science and the popular imagination. The fundamental idea of which profiling is premised – behavior as a reflection of personality – has been the subject of a great deal of misunderstanding, with professionals and nonprofessionals alike questioning whether profiling represents an art or a science and what its function in forensic science should be. To provide a more thorough understanding of criminal profiling’s capabilities and its efficacy as a law enforcement tool, this thesis will examine the application of criminal profiling to investigations, various court rulings concerning profiling’s admissibility, and the role that popular media plays in the perception and function of the practice. It will also discuss how future research and regulatory advancements may strengthen criminal profiling’s scientific merit and legitimacy.
Forensic entomology is an important field of forensic science that utilizes insect evidence in criminal investigations. Blow flies (Diptera: Calliphoridae) are among the first colonizers of remains and are therefore frequently used in determining the minimum postmortem interval (mPMI). Blow fly development, however, is influenced by a variety of factors including temperature and feeding substrate type. Unfortunately, dietary fat content remains an understudied factor on the development process, which is problematic given the relatively high rates of obesity in the United States. To study the effects of fat content on blow fly development we investigated the survivorship, adult weight and development of Lucilia sericata (Meigen; Diptera: Calliphoridae) and Phormia regina (Meigen; Diptera: Calliphoridae) on ground beef with a 10%, 20%, or 27% fat content. As fat content increased, survivorship decreased across both species with P. regina being significantly impacted. While P. regina adults were generally larger than L. sericata across all fat levels, only L. sericata demonstrated a significant (P < 0.05) difference in weight by sex. Average total development times for P. regina are comparable to averages published in other literature. Average total development times for L. sericata, however, were nearly 50 hours higher. These findings provide insight on the effect of fat content on blow fly development, a factor that should be considered when estimating a mPMI. By understanding how fat levels affect the survivorship and development of the species studied here, we can begin improving the practice of insect evidence analysis in casework.
The field of forensic science has been growing and changing with improvements in DNA analysis. One field affected is forensic entomology, which is exploring many ways in which DNA can increase the application of insects in forensic science. One application being explored is the use of insects as a source of human DNA in a criminal investigation. Using flies as a source of foreign DNA can also be utilized in ecological research to conduct surveys on the various species present in different environments. This experiment intends to determine if flies can act as a viable source of alternate DNA. This will be accomplished by an ecological survey of DNA extracted from flies. DNA extractions were performed on flies gathered from parts of the greater Phoenix area. The DNA was then amplified with primers targeting different animal species and examined to observe what animals the flies had come in contact with. Several samples had contamination due to human error and were not able to be evaluated. One DNA extraction out of fifteen yielded pig DNA, indicating flies can be used as a source of DNA. Future experiments should use different animal primers and amplify sections of DNA that can determine the different species consumed by flies. Further research into flies as a DNA source can increase the amount of information available to forensic scientists as well as improve ecologist’s observation of an environment’s biodiversity.