Forensic Entomology and The Law - Current Research and Entomological Findings

Current Research and Entomological Findings

The vast majority of forensic entomological casework consists of establishing a very concrete timeline of the events involved in the crime scene. The new set of data provided by forensic entomological casework undoubtedly provides a solid case for either the defense or the prosecution. But as seen in a new series of experiments, the evidence may not be as firm as previously suspected. The use of DNA in forensic entomology is a growing area of research which will become more prevalent in cases as more research is done. In the first experiment, DNA was extracted from a series of immature blue-bodied blowflies.(blow-fly) The age range of the blowflies varied from first instar larvae up to the third day pupal stage. Extracting the target or victim’s DNA from the gut of the larvae and pupae becomes inconclusive as you reach the third pupal stage. Therefore, as most samples collected from the crime scene can properly denote time scene death, there is a chance that the results may be skewed due to improper specimens.

Once the proper specimens are collected, a series of DNA sequencing tests can be initiated. Several methods of DNA sequencing exist to further analyze the gut material of the insect and eventually track down human microsatellite DNA. The sequencing methods currently utilized by forensic labs include STR or short tandem repeat profiling and HVR or the hyper variable regions of DNA. The current DNA analysis on forensic cases and forensic research indicates that STR profiling is generally successful, whereas HVR sequencing proved to a better choice in DNA testing, as its results had a higher success rate. In new research on the DNA analysis; "STR typing of human DNA from fly larvae fed on decomposing bodies" STR profiling created a complete profile in seven of the thirteen cases, and two cases displayed an incomplete set of alleles whereas four of the cases showed incomplete profiling. On the other hand, HVR sequencing was successful in all cases except one, So there is a slight margin of error when utilizing the STR profiling method of DNA typing in forensic analysis.