Thesis Presentations

On Wednesday, November 16, 2011, Katherine Stang, Aresh Kabirnavaei, and Andrew Roller, all students in the Master’s of Forensic Science program gave thesis presentations to the Forensic Seminar Class. The following paragraphs will summarize each topic.

Katherine Stang presented her thesis titled, Issues in Forensic Identification and the Use of Single Nucleotide Polymorphisms (SNPs). Short Tandem Repeat (STR) technology is a forensic analysis that looks at specific regions or loci found on nuclear DNA. There are 13 core loci that the FBI uses as a standard for the Combined DNA Index System (CODIS). More recently single nucleotide polymorphisms (SNPs) have gotten a lot of attention for its use in forensic DNA testing. A SNP array is variation at a single site in DNA and is the most abundant variation in the human genome with over four million identified in the human genome. Some of the advantages of SNP are their high occurrence in the genome, use in lineage testing due to low mutation rates, and their use in degraded samples by using short amplicons. Ms. Stang presented the following case study as an example of the use of SNPs in degraded DNA samples: a charred femur bone badly degraded by time and environmental conditions was found and though STR failed to type the sample, SNP was successful. Ms. Stang said that further work is needed in the area of SNPs and should include an agreement on how SNPs should be used in forensic labs, additional studies to determine optimal procedures, and research into the area of sexual assault evidence.

Next, Aresh Kabirnavaei presented his thesis titled, Microscopic Characteristics of Carpet Fibers Classified and Indexed to Aid in Identification of Questioned Fibers. According to M...

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...r than 3 mm in diameter. Medium velocity impact spatter usually produces stains between 1 and 3 mm in diameter and may be caused by blunt force trauma or stabbing actions. High velocity impact spatter stains are usually less than 1 mm in diameter and may be produced by gunshots. Reconstructing a crime scene using medium velocity impact spatter may provide information on directionality, point of convergence, and area of origin. Blood spatter analysis can also be used to corroborate witness testimony as to events at a crime scene. Error associated with BPA includes human error, non-uniform formation and rotational offset. Mr. Roller concluded that BPA experts must remember to testify only to the things that they cannot exclude and that more work should be done to determine a universal method for BPA with consistency between crime scenes and different analysts.