Genetics Commons^™

Characterization Of Mitochondrial Dna Repair Components And Repair Choices At Targeted Double-Strand Breaks In Arabidopsis Thaliana, Moira Rodriguez

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Plant mitochondrial genomes are complex when compared to most other eukaryotic mitochondrial genomes. They are large and variable in size, expand and rearrange frequently, abundant in non-tandem repeats, but maintain a very low synonymous substitution rate in the remaining coding regions. Many of these complexities can be explained by the increased use of double-strand break repair for DNA damage. To advance the understanding of mitochondrial genome dynamics as it relates to double-strand break repair, we performed a forward genetics screen to identify proteins involved in DNA repair in plant mitochondrial genomes. Through this screen, we identified an RNA/DNA helicase, Suv3, …

Associations Of Variation In Mtdna With Feed Efficiency In Beef Cattle And The Evaluation Of Transcriptomic Changes In Fetal Kidney Due To Hydrallantois, Lauren Elizabeth Seier

Department of Animal Science: Dissertations, Theses, and Student Research

Project 1 focused on the central role that mitochondria play in ATP production, highlighting that variation within the mtDNA may influence feed efficiency. Variation in the mitochondrial genome was uncovered, and associations with feed efficiency in beef cattle were identified. Growth and feed intake phenotypes, as well as low-pass sequencing, were collected on beef steers across two populations. Protein coding variants were identified and used to classify animals into mitochondrial haplotypes. A linear mixed model was employed, which detected a significant association between mitochondrial haplotype and DMI. A significant haplotype with a variant in Complex I was associated with reduced …

Relationship Between Host Genomics And Microbiomics In Beef Cattle, Andrew D. Lakamp

Department of Animal Science: Dissertations, Theses, and Student Research

As sequencing technology becomes more affordable and throughput increases, microbiome information is becoming more readily available. For beef cattle selection, microbial information has a variety of uses including being a target for genetic prediction or used as a means to explicitly describe additional phenotypic variability in other traits.

Infectious bovine keratoconjunctivitis (IBK), commonly known as pinkeye, is a disease that infects the ocular surface and surrounding tissue which is an animal health and producer economic concern. Vaccinations have shown to have variable effectiveness, while limited genetics studies have suggested that direct genetic selection for resistance would be slow. Therefore, an …

Investigating Associations Between Activity And Performance Traits Across Three Breeds Of Swine Using NuTrack, Dalton R. Obermier

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Feed costs are the largest contributor towards the variable costs of pork production. To decrease feed cost while not sacrificing output requires an improvement in feed efficiency (FE). A potential approach to expand available phenotypes associated with FE is with activity tracking, yet the relationship between activity and performance is not well defined in swine. Therefore, the objective of this study was to quantify associations between activity and feed intake traits. Average daily feed intake (ADFI) was collected on 1,766 purebred boars of three genetic lines (Duroc, Landrace, and Yorkshire) using FIRE (Osborne Industries, Inc., Osborne, Kansas) at a testing …

Hybridization Between The Rare Gray-Headed Chickadee And The Abundant Boreal Chickadee In The Midst Of Shifting Climate, Matthew R. Armstrong

School of Natural Resources: Dissertations, Theses, and Student Research

As species respond to changing climate, distributions and abundances may shift and alter species interactions. Hybridization, a relatively widespread phenomenon becoming more common with climate change, can have beneficial and detrimental effects on population growth rates and genetic integrity. Beneficial effects due to the introduction of advantageous alleles and increased genetic diversity may result from hybridization. Species may also accrue fitness costs associated with changing climates if mismatches occur between environmental variables and phenotypes. The gray-headed chickadee, Poecile cinctus lathami, is an extremely rare songbird that has experienced marked declines in recent decades within its restricted distribution in Alaska …

Heat Stress Changes The Bovine Methylome And Transcriptome And Investigation Of Two Novel Genetic Defects In Cattle, Rachel Renae Reith

Department of Animal Science: Dissertations, Theses, and Student Research

Heat stress is a major concern for livestock producers due to its negative impact on animal health and productivity. Heat stress does so by altering expression of genes through different regulatory mechanisms such as DNA methylation. Understanding how heat stress alters gene expression will help elucidate the genetic basis of physiological changes as well as identify targets for possible heat stress mitigation. The purpose of the first study was to understand how heat stress alters the adipose and skeletal muscle transcriptomes in zilpaterol-fed Brahman, as zilpaterol improves muscle growth and may mitigate the effects of heat stress. Differential expression and …

Heat Stress Changes The Bovine Methylome And Transcriptome And Investigation Of Two Novel Genetic Defects In Cattle, Rachel Renae Reith

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Heat stress is a major concern for livestock producers due to its negative impact on animal health and productivity. Heat stress does so by altering expression of genes through different regulatory mechanisms such as DNA methylation. Understanding how heat stress alters gene expression will help elucidate the genetic basis of physiological changes as well as identify targets for possible heat stress mitigation. The purpose of the first study was to understand how heat stress alters the adipose and skeletal muscle transcriptomes in zilpaterol-fed Brahman, as zilpaterol improves muscle growth and may mitigate the effects of heat stress. Differential expression and …

The Impact Of A Pgym Variant On Myophosphorylase Deficiency In Red Angus Composite Cattle And Changes In The Skeletal Muscle Transcriptome Due To The Intramuscular Administration Of Lidocaine In Wether Lambs, Mackenzie Christin Batt

School of Biological Sciences: Dissertations, Theses, and Student Research

Project 1 focused on eight calves in a Nebraska herd (composite Simmental, Red Angus, Gelbvieh) that displayed exercise intolerance during forced activity. Available sire pedigrees contained a paternal ancestor within 2-4 generations in all affected calves. Pedigrees of the calves’ dams were unavailable, however, the cows were ranch-raised and retained from prior breeding seasons, where bulls used for breeding occasionally had a common ancestor. Therefore, it was hypothesized that a de novo autosomal recessive variant was causative of exercise intolerance in these calves. A genome-wide association analysis followed by whole-genome sequencing led to the identification of a variant in the …

Method Developments To Identify Loci And Selection Patterns Associated With Genotype By Environment Interactions In Soybean, Mary M. Happ

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

For many complex traits such as grain yield, genotype by environment (GxE) interactions are a prevalent source of phenotypic variation. Exploring the capacity of different methodologies to help describe and quantify the GxE interaction landscape for grain yield is an important step in informing plant breeders what the most viable strategies for management and exploitation of GxE may be. In this endeavor, we compared the results from multiple genome wide association studies (GWAS) that used either stability estimators as a phenotype to capture GxE variance, or directly mapped GxE in a mixed model for yield. Leading into this study, a …

Mid-Gestation Maternofetal Inflammation Impacts Growth, Skeletal Muscle Glucose Metabolism, And Inflammatory Tone In The Ovine Fetus During Late Gestation, Zena Mariah Hicks

Department of Animal Science: Dissertations, Theses, and Student Research

Our 1^st and 2^nd studies assessed the impact of mid-gestation maternofetal inflammation on growth, skeletal muscle glucose metabolism, and inflammatory tone in the late gestation ovine fetus. The objective was to determine if inducing maternofetal inflammation during peak placental growth would lead to more profound IUGR characteristics in the fetus. MI-IUGR fetuses exhibited reduced body and skeletal muscle weights and hallmark asymmetric growth at late gestations. Fetuses had higher baseline glucose:insulin ratios and reduced glucose-stimulated insulin secretion. Moreover, hindlimb glucose oxidation was impaired independent of glucose uptake. Skeletal muscle specific glucose uptake and oxidation was reduced in MI-IUGR …

Deciphering The Genetic Architecture Of Key Female Floral Traits For Hybrid Wheat Seed Production, Juan David Jimenez

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wheat (Triticum aestivum L.) is a staple cereal that provides 20% of the calories and proteins in human intake (Ray et al., 2013). Global population is projected to increase to 9.7 billion by 2050. Food production must increase by 70% to feed this future population. Wheat production is in crisis due to political and environmental challenges and is projected to decline by 0.8% in 2022 (FAO, 2022). To ensure food security yield genetic gain must increase by around 1.4% annually. Taking advantage of heterosis, hybrid wheat has the potential to boost grain yield. However, hybrid wheat seed production systems …

Genetic Protocols For Dna Extraction From White-Tailed Deer Cast Antlers To Confirm Individuality, Zach Carter, Brian C. Peterson, Casey W. Schoenebeck, Kimberly A. Carlson

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

White-tailed deer (Odocoileus virginianus) are the most sought-after deer species in America. The antlers of mammals, such as deer, are one of the fastest regenerative tissues in the world and are grown and naturally cast every year. Research on cast antlers have been used for a variety of purposes including population comparisons and impacts of deer health due to climatic stressors. When investigating cast antlers, it is important to confirm individuality of match sets in addition to antlers of the same individual between years. Therefore, individuality must be confirmed genetically, and protocols must be developed and established to …

Exploration Of Genes Controlling Grain Yield Heterosis In Hybrid Wheat (Triticum Aestivum L.) Utilizing 3ʹ Rna Sequencing, Nichole Lynn Miller

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The implementation and future success of hybrid wheat (Triticum aestivum L.) is impacted by breeders’ inability to create consistent high yielding, high heterosis hybrids. This research addresses this problem by conducting an exploration of transcriptomes from hybrids and parent lines to determine what genes are active in heterotic or non-heterotic hybrids and how their level of expression can explain the phenotype of grain yield heterosis. Using hybrids that showed positive mid-parent heterosis (MPH), classified as heterotic in our study, and negative or no difference MPH hybrids, classified as non-heterotic, differentially expressed genes (DEGs) potentially related to heterosis and hybrid …

Development Of High Value Oil Traits Using The Model Oilseed Crop Camelina Sativa, Evan Updike

Department of Biochemistry: Dissertations, Theses, and Student Research

Plant oils are an important source of food, fuel, and feed in our society today. The oil found in the seeds of plants is composed almost entirely of triacylglycerol (TAG) molecules, which consist of three fatty acids esterified to a glycerol backbone. As crude oil supplies decline, vegetable oils are gaining traction as a renewable substitute to petroleum-based materials in fuels, lubricants, and specialty oleochemicals. However, as it currently stands vegetable oils do not possess the properties necessary to fill the void of a petroleum free world.

To address this problem, plant biotechnologists have done extensive work on genetic engineering …

Production, Evaluation, And Selection Of Elite Quality Protein Popcorn (Qpp) Hybrids, Leandra Marshall Parsons

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

In 2017, twelve Quality Protein Popcorn (QPP) inbred lines were developed and selected as premier dent by popcorn crosses fit for hybridization and testing. These QPP inbred lines were derived from specific Quality Protein dent Maize (QPM) by ConAgra Brands® popcorn line crosses to produce high lysine, vitreous popcorn lines capable of near-equal popping characteristics compared to the original popcorn parents. The QPP hybridization project commenced in the summer of 2018 utilizing these 12 inbred QPP lines and crossing them in a full diallel. Since then, the production of QPP hybrids has employed a diverse set of selection factors evaluating …

Using Crispr-Cas9 To Construct Knockout Mutants In Dna-Repair Genes In Arabidopsis Thaliana, David Campbell

Honors Program: Senior Projects (Public)

The mitochondria are known as the powerhouse of the cell, and just like a real powerhouse, it can be a dangerous place to store sensitive information. Energy generation and redox reactions in the mitochondria can cause damage to the DNA stored there, resulting in a higher mutation rate. Compared to their animal counterparts, however, plant mitochondria exhibit a lower mutation rate and a higher recombination rate. It is hypothesized that the unique DNA repair methods present in plant mitochondria are responsible for the phenomena observed there. To study the mechanics of DNA-repair in this organelle, however, researchers must be able …

Inheritability Of Ciprofloxacin-Induced Mitochondrial Mutations From Parental To Offspring Generation Using Quantitative Polymerase Chain Reaction, Rose Mccoy

Honors Program: Senior Projects (Public)

In all eukaryotes, mitochondria are known as the powerhouse of the cell (Siekevitz, 1957). In plants, however, their mitochondrial genome is especially strange. Plant mitochondrial genomes are extremely large and contain both linear and circular subgenomic DNA fragments. Plant mitochondrial genomes undergo a significant amount of mutations in the form of rearrangements. However, it is not known how often these rearrangements are inherited by the next generation. It is thought that plant cells that are still dividing have higher rates of DNA repair, such as double-strand break repair, to ensure the quality of that plant lineage. As follows, it is …

Evolutionary And Ecological Determinism Of Host Specificity In Arthropod Parasites, Joseph Levey

UCARE: Research Products

Understanding why some diseases infect more species than others is crucial for predicting where and when disease will spread, which can inform the management of wildlife, agriculture, and human health. Currently, large scale patterns of host-parasite dynamics are being studied to understand where to look for and how to manage emerging human diseases (Leroy 2005; Benelli 2018). Previous research has used the Global Mammal Parasite Database (GMPD) to look at host breadth—the number and diversity of species a pathogen can infect—for various groups of parasites, e.g. helminths, arthropods, fungi, etc., from a host-centric perspective (Stephens et al. 2017; Park et …

Genetic Studies Of Wildlife, Brittaney L. Buchanan

School of Natural Resources: Dissertations, Theses, and Student Research

Genetic techniques are being more frequently used to understand the biology and management of wildlife species. The wild turkey is one species of genetic interest because the correct identification of individuals to the subspecies level is difficult using traditional methods. Currently phenotypic differences in plumage, especially the upper tail coverts, are used to assign individuals to subspecies. To hunters wanting to complete a “grand slam,” identification of birds’ subspecies is important. This study focuses on the five extant subspecies: Eastern (M. g. silvestris), Osceola (M. g. osceola), Rio Grande (M. g. intermedia), Merriam’s ( …

No Association Between An Oxytocin Receptor Genetic Variant And Depressive Symptoms, Rachel Sisley, Grace Sullivan, Scott Stoltenberg

UCARE: Research Products

• Depression has the greatest impact on daily functioning capability of all diseases and adversely effects individuals globally (Flint & Kendler, 2014). • Human capital value of these losses has been about $40 billion dollars annually (Kessler, 2012). • Analysis of the genetic and biological systems associated with depressive symptoms, such as the oxytocin system, could lead to identifying risk variants and possible treatment development. • Genetic Variation in OXTR is associated with a variation in depressive symptoms including low selfesteem, pessimism, and low self-efficacy, etc. (Conner et al., 2018). • The A allele of the SNP rs53576 is considered …

Terms Of Service: The Use And Protection Of Genomic Information By Companies, Databases, And Law Enforcement, Sophia Kallas

Honors Program: Senior Projects (Public)

Private genomic companies have become a popular trend in the last two decades by providing customers with information regarding their ancestry and health risks. However, the profiles received from these companies can also be uploaded to public databases for various purposes, including locating other family members. Both testing companies and public databases have private interests, and both are at risk of law enforcement intervention for the purpose of forensic familial searching. There is little federal legislation protecting the privacy of an individual’s genetic profile. Consequently, it has been up to federal agencies, state laws, and judicial precedents to prevent the …

Addressing The Challenges Facing Wheat Production: Nebraska And International Breeding Efforts, Sarah Blecha

Doctor of Plant Health Program: Dissertations and Student Research

Bread wheat, Triticum aestivum L., provides 20 percent of the global daily calorie intake. It is the third most important food crop, after rice and corn. Biotic challenges significantly reduce wheat yield; chemical control can be a solution but can be cost prohibitive for subsistence farmers. For many farmers, genetic resistance to biotic stresses can be the most cost effective solution.

The International Center for Agricultural Research in the Dry Areas (ICARDA) and the Nebraska Small Grains Breeding Program have been addressing these wheat production challenges. ICARDA is part of an international research consortium to increase wheat yield and tolerance …

Genome-Wide Association Studies In Maize And Sorghum, Preston Hurst

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Genome-wide association studies are used to identify genetic variants associated with a particular phenotype. GWAS has been used in a variety of taxa, from humans, to fish to plants . The present analysis is focused on two species important to the human species: maize and sorghum. A GWAS in maize was carried out on the modification of the Ga1-s allele. The Ga1 locus has long been studied as being involved in a unilateral crossing barrier . However, it has long been suspected that the locus is modified by background genetic factors . GWAS was used to observe candidates for this …

Plant Mitochondrial Genome Evolution And Structure Has Been Shaped By Double-Strand Break Repair And Recombination, Emily Wynn

School of Biological Sciences: Dissertations, Theses, and Student Research

Plant mitochondrial genomes are large but contain a small number of genes. These genes have very low mutation rates, but genomes rearrange and expand at significant rates. We propose that much of the apparent complexity of plant mitochondrial genomes can be explained by the interactions of double-strand break repair, recombination, and selection. One possible explanation for the disparity between the low mutation rates of genes and the high divergence of non-genes is that synonymous mutations in genes are not truly neutral. In some species, rps14 has been duplicated in the nucleus, allowing the mitochondrial copy to become a pseudogene. By …

Investigating The Role Of Free Radicals In Huntington's Disease Using Drosophila Melanogaster, Jennifer Libov

Honors Program: Senior Projects (Public)

During normal cell metabolism, reactive oxygen species (ROS) are produced as a byproduct of oxidative phosphorylation. ROS are utilized in the cell as a signaling molecule and can be maintained at healthy levels by cellular antioxidants. However, when the cell experiences oxidative stress due to environmental or genetic conditions, levels of ROS can exceed healthy levels and inhibit necessary life functions by damaging biomolecules and cellular structures. This loss of function can lead to physiological decline and neurodegeneration, such as in diseases like Alzheimer’s, amyotrophic lateral sclerosis (ALS), and, potentially, Huntington’s disease. The following experiments use the model genetic organism …

Generation And Evaluation Of Modified Opaque-2 (O2) Popcorn Suggests A Route To Quality Protein Popcorn (Qpp), Ying Ren

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

I have been working on a Quality Protein Popcorn breeding project where QPM conversion is carried out simultaneously for several elite popcorn germplasms. During my study in the graduate program, I led the following aspects of the Quality Protein Popcorn Breeding Project:

1. Identified suitable QPMs as opaque-2 allele donors.

2.Examined the feasibility of quick introgression of the opaque-2 allele into popcorn lines via marker-assisted selection.

3. Monitored modification by SDS-PAGE zein profiling and light box phenotypic selection to make sure multiple modifier loci for opaque-2 were incorporated each time generation advancement was carried out.

4. Carried out high throughput …

The Effect Of Maoa And Stress Sensitivity On Crime And Delinquency: A Replication Study, Christa C. Christ, Joseph A. Schwartz, Scott F. Stoltenberg, Jonathan R. Brauer, Jukka Savolainen

Department of Psychology: Faculty Publications

Across several meta-analyses, MAOA-uVNTR genotype has been associated with an increased risk for antisocial behavior among males who experienced early life adversity. Subsequently, early life stress and genetic susceptibility may have long-term effects on stress sensitivity later in life. In support of this assumption, a recent study found evidence, in two independent samples, for a three-way interaction effect (cG × E × E) such that proximate stress was found to moderate the interactive effect of MAOA-uVNTR and distal stress on crime and delinquency among males. In light of recent developments in cG × E research, we attempted to …

Breeding For Resistance In California Strawberry To Verticillium Dahliae, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

This article focuses on breeding resistant strawberries to the fungus Verticillium dahliae, common name Verticillium wilt. This is a serious fungal disease that can result in a loss of 50% or more of a strawberry harvest when grown in infested soil. The main goal is to provide an example of how a cultivar can be made more resistant to a plant pathogen with the use of plant breeding methods.

Since 1930 the University of California, Davis, has been developing strawberry cultivars that are adapted to the agricultural industry and regional farms. Developing cultivars that require fewer inputs are of …

Copy Number Variation In The Porcine Genome Detected From Whole-Genome Sequence, Rebecca Anderson

Honors Program: Senior Projects (Public)

Copy number variations (CNVs) are large insertions, deletions, and duplications in the genome that vary between individuals in a species. These variations are known to impact a broad range of phenotypes from molecular-level traits to higher-order clinical phenotypes. CNVs have been linked to complex traits in humans such as autism, attention deficit hyperactivity disorder, nervous system disorders, and early-onset extreme obesity. In this study, whole-genome sequence was obtained from 72 founders of an intensely phenotyped experimental swine herd at the U.S. Meat Animal Research Center (USMARC) in Clay Center, Nebraska. This included 24 boars (12 Duroc and 12 Landrace) and …

Alcohol Intoxication Moderates The Association Between A Polygenic Risk Score And Unprovoked Intimate Partner Aggression, Christa C. Christ, Laura E. Watkins, David Dilillo, Scott F. Stoltenberg

Department of Psychology: Faculty Publications

Despite evidence that genetic variation contributes to aggression, few studies have examined how genetic variation contributes to IPA specifically. In the current study, 69 couples from a Midwestern university completed self-report measures of IPA, childhood trauma exposure, and hazardous alcohol use, and were randomly assigned to consume either a placebo or alcohol beverage before participating in an analogue aggression task against their partner. Genetic risk (i.e., association with lower transcriptional efficiency) for aggression was measured with a polygenic risk score (PRS) created from four polymorphisms (HTR1B rs13212041, HTR2B rs6437000, 5-HTTLPR, and MAOA uVNTR). Among individuals with a low PRS, …