Forensic Biology Commons^™

From Genes To Streams: Mitochondrial Approaches To Population Monitoring Of The Santa Ana Sucker Catostomus Santaanae, Mariana Antonio

Electronic Theses, Projects, and Dissertations

This study was developed to use aquatic environmental DNA (eDNA) as a tool to detect the presence of the Santa Ana sucker (Catostomus santaanae), a federally threatened fish species, across the Santa Ana River in Southern California. Environmental DNA is any genetic material that an organism sheds into the environment. We can get an idea of what aquatic species are present when sampling water at a given site. We sequenced the complete mitochondrial genome (mitogenome) of the Santa Ana sucker and designed custom DNA primers to improve eDNA detection accuracy. These primers were selected based on high genetic …

(R2167) Global Stability Of Seirs Model With Single Dose Vaccination In Varying Population, Govind Jha, Prabhat Mandal, Sarita Jha

Applications and Applied Mathematics: An International Journal (AAM)

Understanding the evolution of infectious diseases within a dynamic population is essential for formulating effective public health strategies. This work introduces an enhanced SEIRS epidemic model that incorporates demographic variation and a single-dose vaccination strategy, supporting that immunity can be reduced over time. The model reflects diseases in which individuals may return to the susceptible state after recovery. Extending prior reduced three-dimensional models, this study develops a complete four-dimensional SEIRS framework, thereby increasing the model’s applicability to real-world scenarios. The inclusion of the full system presents greater analytical challenges. To overcome this, we extend the second additive compound matrix and …

Exploring Biogeographical Ancestry Inference Of New York Residents Using A 45 Indel Panel, Amanda Martinez

Student Theses

Biogeographical ancestry (BGA) inference is an important tool in forensic science, providing supplemental information when comparison/reference DNA is not available for traditional DNA analyses. Insertion/deletion polymorphisms (INDELs) have been used in the last decade as ancestry-informative markers (AIMs) for BGA inference because they can be easily adapted to forensic-type samples and are determined using low cost and easy processing methods. Limited research has attempted to estimate ancestry and admixture in United States (U.S.) populations. This study evaluated the effectiveness of a 45- and 21- INDEL panel to measure population admixture proportions of four different origins (African, European, East Asian and …

The Longevity Of Dna From Bloodstains And Its Forensic Implications, Nadia Walter

Senior Honors Theses

Human DNA is valuable forensic evidence, helping to solve a wide range of cases. It is often sourced from biological fluids found at a scene such as blood, saliva, semen, and urine. Many different factors can influence the longevity of DNA sourced from bloodstains, including the type of substrate, storage conditions, and weather. The quality of a DNA sample from a bloodstain found at a crime scene may influence its admissibility in court.

Original research was done on a surgical table from the last major battle of the American Civil War, extracting DNA from latent bloodstains. Some full profiles were …

Decomposition Study Using Pigs In Southeastern Nebraska During The Fall And Winter Seasons, Ryan Bodine

Department of Anthropology: Theses and Student Research

When an individual is found deceased, one of the tools used in the identification process is estimating the post-mortem interval (PMI). This estimate is used to determine how long an individual has been deceased once their remains are found. To estimate an accurate PMI, knowing how decomposition is affected by external factors is key. The transition period from fall to winter in southeastern Nebraska consists of fluctuating temperatures as the seasons transfer from fall to winter. This thesis investigates how decomposition is affected during this transition period while also looking at two different environments that are common in Nebraska, prairies …

From Prairie To Practice: Forensic Taphonomy, Ethics, And Regional Ecology In Southeastern Nebraska, Jessica F. L. Gammage

Department of Anthropology: Theses and Student Research

Forensic taphonomy examines the postmortem processes that affect human remains within specific environmental contexts and plays a critical role in medicolegal death investigation. Despite significant advances in decomposition research, experimental studies remain geographically and environmentally uneven, limiting the transferability of postmortem interval (PMI) estimation methods across regions. The Central Great Plains are underrepresented in forensic taphonomic research despite its distinct ecological and geomorphological characteristics.

This thesis evaluates southeastern Nebraska as a specific regional setting for forensic taphonomic research by integrating ecological, pedological, and geomorphological data with current forensic literature. Tallgrass prairie vegetation, loess-derived soils, seasonal moisture variability, and dynamic fluvial …

Understanding Roma Oppression In Europe Through Humantarian Forensic Analysis, Christal L. Quinn

Department of Anthropology: Theses and Student Research

This thesis examines the marginalization of Roma people in Europe, and how humanitarian forensic practices may help Roma communities in their quest for justice and recognition. The study draws exclusively on secondary information to examine the social, political, and legal issues affecting the Roma communities, who have endured centuries of institutional discrimination, marginalization, and violence. This thesis identifies ways in which systematic oppression continues to limit Roma communities’ access to education, housing, healthcare, and legal protection through a review of relevant literature and applicable theoretical frameworks. The study also examines the relevance of forensic science, particularly its humanitarian applications, in …

Rehumanizing Anatomized Individuals: Using Osteobiographies As A Step Towards Reparative Justice, Lillie C. Turpin

Department of Anthropology: Theses and Student Research

In 1985, India banned the export of human remains. This ended the major trade route for primarily US and European anatomical supply companies. Until this point, companies like Carolina Biological Supply exploited and erased vulnerable people's identities, molding them into anonymous anatomical specimens. This study investigates the life and postmortem history of twenty-five individuals, previously used as anatomical specimens, housed at the University of Nebraska–Lincoln. Using an osteobiographical approach, this research reconstructs aspects of these individuals' lived experiences and examines how anatomical preparation practices reflect structural violence and apathy.

Skeletal analysis of twenty-five individuals revealed a range of biological profiles, …

Non-Destructive Automated Classification Of Human And Large Mammal Long Bone Fragments: A Deep Learning Approach Using Micro-Ct Histomorphology And Grad-Cam Interpretation, Kathleen Marie Kelley

Department of Anthropology: Theses and Student Research

This study explores the development and validation of an automated, deep learning system designed to differentiate human from large mammal long bone fragments using micro-CT imagery. A comprehensive dataset of cross-sectional µCT images was assembled from human and animal skeletal material processed at the DPAA, Nebraska. A convolutional neural network (CNN) based on a ResNet-18 architecture, utilizing transfer learning from ImageNet weights, was trained to classify µCT images as human or animal. The model achieved a mean classification accuracy of 89.85% (± 8.27%) across five sample-level cross-validation folds, with a sensitivity of 96.21% and a 95% bootstrap confidence interval of …

Exploring The Biocultural Profile Of The Undocumented Populations Of The Sonoran Corridor: A Skeletal Assessment Of The Prevention Through Deterrence Strategy, Mary A. Vaughn

Department of Anthropology: Theses and Student Research

Over the last thirty years the mortality rate of the undocumented population at the US-Mexico border has risen, requiring methods distinguishing US-born individuals from immigrants to improve the likelihood of identification and repatriation through foreign consulates. Forensic anthropologists with the Pima County Office of the Medical Examiner (PCOME) have advocated for the use of the biocultural profile, combining the biological profile with factors including oral health, osteological stress, and personal effects. The biocultural profile serves two purposes, functioning both as a tool for identification and with which to document structural inequality within communities of origin.

This study examines changes in …

Pepper Spray Exposure And The Effect On Dna Profiling Of Blood, Brandon Schmakel

Honors Projects

Pepper spray is a common self defense tool used in both law enforcement and civilian settings, with the goal of incapacitating the sprayed individual. In real casework where pepper spray was used, a red-brown stain which tested positive presumptively for blood provided no DNA profile after further testing six months later. A previous graduate student, Emma Crawn, attempted to emulate these casework conditions and instead achieved a DNA profile with slight indications of inhibition or degradation. Further analysis of active pepper spray ingredients such as Oleoresin Capsicum (OC) and Chloroacetophenone (CN) reveals that there are observed reactions, such as oxidation, …

Characterization Of The Human Thnatomicrobiome By Decomposition Stage Through Bioinformatic And Meta Data Analysis, Ashton C. Laughlin

Biology Theses

Estimating the postmortem interval (PMI) is one of the most crucial factors in forensic death investigations. Recent advances in forensic microbiology have led to increased interest in using the study of the human postmortem microbiome, or “thanatomicrobiome,” to improve PMI estimates. In addition to current PMI estimation techniques, microbial community succession could serve as a valuable tool in estimating PMI. Further research is needed to develop a comprehensive understanding of the human postmortem microbiome. The purpose of this study is to contribute to the expansion of this tool by reviewing the current literature and analyzing previously published data using the …

Differentiation Of Cell Populations In Saliva-Skin Mixtures Using Autofluorescence Profiling, Kara Fairfax

Master of Science in Forensic Science Directed Research Projects

While DNA profiling of sexual assault evidence can identify biological contributors, determining the tissue source of recovered profiles remains a significant challenge, particularly in cases of suspected oral assault involving mixtures of epithelial cells. The initial goal of this study was to identify non-genetic signatures for differentiating two types of epithelial cells relevant to oral assaults, saliva epithelial cells and epidermal skin cells. To develop tissue-specific signatures, reference cell populations from saliva and epidermal skin surfaces were collected from 20 donors and analyzed using full spectrum flow cytometry.

Results from single-source reference samples showed that saliva-derived particle populations exhibited higher …

(R2150) Impact Of Specialist Predator Harvesting On The Stability Of A Three-Species Food Chain Model With A Generalist Predator, S. Ganga, S. Vijaya

Applications and Applied Mathematics: An International Journal (AAM)

In this study, the stability of a three-species food chain model comprising a prey, an intermediate specialist predator, and a top predator exhibiting generalist behavior is examined, with harvesting applied to the intermediate predator. The main objective is to investigate how variations in the harvesting rate influence system stability and the coexistence of all three species. The positivity, boundedness, and equilibrium points of the model are analyzed to ensure biological feasibility. The equilibrium point involving the prey and the top predator satisfies the criteria for both local and global asymptotic stability. The coexistence equilibrium point attains local asymptotic stability based …

Capillary Electrophoresis Vs Massively Parallel Sequencing: A Cost-Benefit Analysis, Samia Williams

Honors Projects

Massively Parallel Sequencing (MPS) is a new Forensic Science field allowing multiple samples to be sequenced simultaneously. In contrast to CE, multiple types of genetic markers including those from different nucleic acids can be used in the same assay. Additionally, MPS has opened the doors to certain fields of Forensic DNA Analysis like Forensic Investigative Genetic Genealogy and Forensic Phenotyping assays containing upwards of 100 SNPs. While quite expensive and requiring a high cost for initiating, MPS has the potential to save time and greatly increase the throughput of Forensic DNA Analysis in crime labs.

Buffer Vs. Swabs: Efficacy Of Carrier Nucleic Acids In Robotic Extractions, Shawn Cecil

Honors Projects

This study compared the efficiency of two carrier nucleic acid methods, specifically using salmon sperm DNA (spDNA), in robotic solid-phase extractions of cotton swab samples. Robotic extractions reduce processing time and workload but result in substantially lower DNA recovery than manual organic extraction. This research tested 10 µg of spDNA being added to the lysis buffer or pre-treating the swabs with it before DNA was added. Both methods showed a significant increase in recovery compared to extractions with no carrier. In the buffer extractions, recovery ranged from 69.4% to 117.5% and the swabs being pre-treated ranged from 84.2% to 125.8% …

Applicability Of Cementochronology To Estimate Season-Of-Death In Humans: Insights From Modern Documented Collections, Olga Ibarra-Sanchez

Theses and Dissertations

Dental cementum is characterized by lifelong deposition of alternating opaque annuli in fall/winter and translucent bands in spring/summer. This study aims to test the applicability of cementochronology to estimate season-of-death, by observing the properties of the last layer, with direct implications for forensic anthropology and bioarchaeology. The sample includes canine teeth from 146 adults (84 males, 62 females), age-at-death ranging from 20-97 years (mean=61.7 years, SD=18.6 years), from two contemporary skeletal collections. Of these individuals, 78 (53.4%) died in spring/summer and 68 (46.6%) died in fall/winter. Overall accuracy was low at 64.4% (94/146). Accuracy was higher for spring/summer deaths 100.0% …

Decomposition Processes And Insect Indicators In Forensic Investigations, Eli Taylor

University Honors Theses

Insects play an essential biological and ecological role in human life, and their predictable relationship with decomposing remains has positioned them as a cornerstone of modern forensic science. Since the early 20th century, forensic entomology has provided critical evidence for estimating the postmortem interval (PMI), relying on patterns of colonization, species succession, and insect developmental timelines. Accurate PMI estimations are vital to medicolegal investigations, influencing the interpretation of biological evidence, guiding resource allocation, and informing determinations of cause and manner of death. However, insect activity is profoundly shaped by environmental and ecological variables, including temperature, humidity, seasonal shifts, and geographic …

The Micro-Communities Of Trees, Nicholas Davis, Lily Boysworth, Westen Wilburn

Fall Showcase for Research and Creative Inquiry

This study investigated how tree species diversity influences the variety of organisms living on or around trees across different habitat types. Field data were collected through random tree selection, measurement of tree diameter, identification of species, and estimation of surrounding ground cover types such as grass, herbaceous plants, woody plants, and leaf litter. Biodiversity associated with each tree was analyzed using the Shannon Diversity Index across several ecosystems, including grassland, woodland, and pond environments. Results indicated that the pond ecosystem exhibited the highest species diversity, followed by woodlands and then forests. A range of organisms, including lichens, mites, fungi, and …

Nueva Metodología De Análisis Para Determinar El Delito Ambiental De Ecocidio Por Glifosato En Cultivos Permanentes De Coca En Colombia, Rosalina González Forero, Jerry H. Kavouras, Érika González Ruiz

Biology Department Faculty Articles

El crimen organizado transnacional ha sido nefasto para el territorio colombiano, en especial el asociado a la producción de coca en la última década, lo que ha generado impactos económicos y sociales debido al aumento del conflicto e inseguridad en las zonas de influencia del cultivo. Esto se debe a que en el 2023 se tenían 230 000 hectáreas sembradas, lo que representa el 20 % de la superficie del país, con un impacto ambiental no cuantificado en términos penales. Este requiere de acciones de entidades estatales, así como de cooperación internacional, para adaptar estrategias y poder judicializar estos delitos …

Indirect Dna Transfer To Duct Tape Rolls Stored In Cars, Yuching Chung

Student Theses

This project investigated the accumulation of DNA on duct tape rolls stored in cars. Specifically, we analyzed samples recovered from three areas (the inside, outside, and flat sides) of unused duct tape stored under the driver's seat and trunk of cars for seven days. Twelve volunteers were recruited, resulting in 64 DNA samples from 12 cars. We evaluated DNA quantities and STR genotyping outcomes after amplification with the GlobalFiler™ kit. On average, the DNA yields from under the driver's seat were higher than from the trunk, but the difference was not significant. The inside of the tape roll yielded significantly …

Characterization Of Dna Background On Duct Tape Stored In Domestic Environments, Elaan A. Lukasiewicz

Student Theses

With lower detection limits for forensic DNA analysis, it is important to have a better understanding of background DNA levels unrelated to the crime to facilitate accurate data interpretation. Duct tape is used in crimes, e.g. to bind victims and seal drug packaging, and may be tested for DNA. To determine DNA background levels, twelve volunteers were recruited to donate a used roll of duct tape from their home. The duct tape was divided into three areas: inside, outside, and sides of the roll, and swabbed for DNA. The average concentration of DNA was determined for the inside (0.0723 ng/µL …

Str Analysis Performance Comparison For Two Capillary Electrophoresis Instruments: The Seqstudio And The 3500 Genetic Analyzers, Yana Leichyk

Student Theses

This study compares the performance of two capillary electrophoresis instruments—the SeqStudio™ Genetic Analyzer and the 3500™ Genetic Analyzer—for forensic short tandem repeat (STR) analysis. Using the GlobalFiler STR kit and certified reference material (SRM 2391d), five key performance metrics were evaluated: sizing precision, signal reproducibility, detection sensitivity, mixture resolution, and overload tolerance. STR profiles were generated from single-source and mixture samples with DNA inputs ranging from 500 pg to 15.6 pg. Both instruments met the < 0.15 bp sizing precision requirement for forensic casework. Signal reproducibility tests showed that the SeqStudio often produced higher average RFU values, but with greater variability, while the 3500 demonstrated more stable signal performance across days and samples. Mixture detection was effective on both platforms up to 1:10 ratios. Dropout of minor alleles began to appear at 1:20 ratios, especially in green and yellow dye channels, on both instruments. Sensitivity studies confirmed full profile recovery down to 62.5 pg, with increasing allelic and locus dropout at lower inputs. Enhanced injection voltage (1.5 kV) did not improve low-template performance. In overload testing (1–5 ng input), the 3500 maintained a consistent signal output, while the SeqStudio exhibited signal suppression at 5 ng, likely due to internal normalization. The SeqStudio exhibited better spectral overlap compensation, with fewer occurrences of spectral bleed-through artifacts. These findings support the use of both platforms in forensic casework, while emphasizing the importance of platform-specific calibration and analytical threshold settings for optimal performance.

Color Tests For The Presumptive Identification Of A Range Of Benzodiazepines, Regan Mulvin

Honors Projects

Color tests are presumptive chemical tests that determine the class of drug in both laboratory and field settings. Despite the rising popularity of benzodiazepines and the usefulness of color tests, there is no widely accepted color test for identifying them. This study tested six different color tests against five benzodiazepines, including diazepam, clonazepam, lorazepam, alprazolam, and flualprazolam, to identify which of the tests would work most generally across all benzodiazepines. Of the six tests, the McKibben test, the Janovsky test, and the Zimmerman test all showed potential usefulness as a presumptive color test. More studies should be done on a …

Oviposition And Immature Development Of Blowflies In Forensic Investigations, Amalia Herrera-Benitez

Themis: Research Journal of Justice Studies and Forensic Science

Forensic entomology is a subspecialty within the field of forensic science where insect evidence is analyzed to solve criminal cases. Insects begin to colonize the body, with blowflies being the first insects to arrive. Within minutes, blowflies can lay eggs on a decomposing body, and the larvae will feed once they hatch. The life cycles of blowflies are analyzed to help determine an estimated post-mortem interval (PMI), which is crucial in investigations, as it can help establish a timeline. Various factors, such as temperature and access to the body, can cause delays in the oviposition of blowflies. A delay in …

Dna Extraction And Species Determination Of Historic Museum Pelt Samples, Selin Ates

Student Theses

The identity of the fur covering the sculpture named Object in the Museum of Modern Art has remained a mystery since its creation in 1936 by Meret Oppenheim. DNA testing can possibly provide an answer, but to preserve the integrity of the sculpture, only a very small piece of the fur can be sampled. Prior to testing Object, testing using museum samples was performed to determine whether DNA of a sufficient quantity and quality can be extracted and sequenced. Several DNA extraction and sample washing methods were tested to examine the effects on the DNA of museum pelts aged …

Advancement Of Wrongful Conviction Prevention Strategies In Forensic Science, Isabella Pinto

Honors Projects

The National Registry of Exonerations (NRE) has identified 1,051 of its logged cases to involve forensic evidence in some way, nearly one-third of the total 3,600 exonerations in its database. Analysis of the NRE and Innocence Project databases revealed the most common factors in forensic-related wrongful convictions: expert testimony, flawed methodologies (most of which are no longer in use), and statistical misinterpretations of results. The majority of scholars agree that oversight in forensic casework must be improved in order to meaningfully resolve issues. Creation of commissions in each state would address all of the identified errors, though not a catch-all …

Investigation Into The Microbiome Of Blow Fly Eggs Using Microseqtm Id, Samantha S. Davis, Drusilla Sheridan, Jennifer Rosati

Undergraduate Research

There is little published research characterizing the microbiome associated with blow fly eggs and how they may affect the colonization behaviors of certain blow fly species. Once deposited, blow fly eggs are rapidly introduced to a diverse range of microorganisms, which can vary depending on the species of blow fly, the environment, and the decomposition stage of the substrate (Junqueira et al., 2017). Since blow flies are among the first insects to colonize decomposing remains, the microbial communities present on their eggs could serve as key indicators of the decomposition stage at the time of egg-laying, thus providing a potential …

Passive Dna Transfer To Fidget Blasters Stored In Cars, Rachel Chan

Student Theses

This study evaluated the amount of detectable DNA accumulated on clean plastic fidget blasters, used to simulate firearms, over a seven-day storage period inside a vehicle. Twelve volunteers were asked to place one fidget blaster each in the glove box and underneath the driver’s seat from behind. After the seven-day period, the volunteers returned the fidget blasters, donated a reference sample, and filled out a questionnaire. The grip, slide, and trigger were swabbed for DNA and extracted. The extracts were quantified to determine the concentration of human DNA, and if the samples met the PCR threshold to be genotyped. The …

A Qualitative Nmr And Histological Analysis Of Adipocere Formation In Different Aqueous Environments Using Sus Scrofa Models, Mia M. Sorrentino

Student Theses

Adipocere is a wax-like crust that has the potential to form over corpses in moist, humid, and anaerobic environments, preserving them in a process similar to that of mummification. The substance can be identified within 3-6 months postmortem and is characterized by the ratio of saturated fatty acids to unsaturated fatty acids. Palmitic acid and stearic acid are the most abundant in comparison to myristic and oleic acids. The goal of this study was to investigate factors affecting adipocere formation in different aqueous environments. Pork belly samples were submerged in water samples collected from different places around New York City …