“Jump and Swing Your Tail: What We Can Learn From Escaping Kangaroo Rats”
Extreme organismal behaviors can be used to identify physical mechanisms organisms use to overcome mechanical constraints in their natural environment. Kangaroo rats, bipedal hopping rodents, use erratic vertical leaps — up to ten times their hip height — to outjump predators.
Such performances require extraordinary power that exceeds the physical limits of what muscles alone can produce. Kangaroo rats circumvent this limitation by using their Achilles tendons in two distinct ways: as a strut to transfer energy from large proximal muscles, and to decouple shortening velocities of the distal muscles, allowing them to operate at near optimal conditions for power production. During the airborne phase of their escape response, these animals use their tail to reorient themselves. By rotating the tail around the body, bending and twisting, a kangaroo rat can change the direction it is facing.
Outcomes of this research provide a foundation for understanding principles governing the mechanics of extreme behavioral phenomena and explore the limits of biomechanical performance. Together, providing the necessary groundwork to augment designs of robotics and human assistive devices, like prosthetics.
Marie Janneke Schwaner is a doctoral student in Biological Sciences studying under Dr. Craig P. McGowan
“Characterizing Genetic Regulatory Elements in Sheep”
The genetic sequence in all cells in an individual are the same therefore each specific tissue requires control of the relevant complex of genes. Regulatory elements dictate which areas of the genome are active and repressed, ensuring that the genes required for each specific cell are expressed, allowing it to function properly. These regulatory elements have been defined in few mammalian species across multiple tissues. The objective of this study is to identify the locations of gene regulatory elements in sheep by characterizing histone modifications in different tissues. Chromatin immunoprecipitation paired with sequencing (ChIPseq) was conducted for four histone marks; H3K4me3, H3K27ac, H3K4me1, and H3K27me3 known to be related to active or repressed of gene regulatory elements. Regions of the genome that promote and repress gene expression were identified for 47 tissues. Approximately 15% of the genome was considered in a state of active, poised, or repressed chromatin states across tissues. Considering only about 2% of the genome is protein coding, this project allows us to understand the function of more of the genome in sheep. The functional annotation of the sheep genome is essential for understanding gene regulation and potential mechanisms that influence economically important traits.
Kimberly Davenport is a doctoral student in Animal & Veterinary Science studying under Dr. Brenda Murdoch
3rd Place & People’s Choice Award
“Microbial Metabolomics: From Manure to Bioplastics”
My research aims to characterize metabolomes within undefined mixed microbial consortia (MMC) to better understand what factors inhibit and/or enhance efficient conversion of volatile fatty acids (VFAs) into polyhydroxyalkanoate (PHA), a compound used in biodegradable plastics. I apply Liquid chromatography–mass spectrometry (LC/MS) metabolomics methods to uncover “feast” PHA metabolisms of MMC cultured on fermented dairy manure; “feast” metabolisms induced under aerobic dynamic feeding (ADF) remain poorly understood, with only limited molecular-level exploration.
These results will enhance understanding of MMC cultured on real wastewaters, MMC metabolome dynamics when synthesizing PHAs, better describe feast-famine response, and identify critical metabolites involved in PHA synthesis. Producing bioplastics from dairy manure utilizing MMC can provide a sustainable solution to help alleviate environmental challenges associated with manure nutrient runoff, and curb petroleum-based plastics pollution.
Maribel Alfaro is a master's student in Civil & Environmental Engineering studying under Dr. Erik Coats.
“Gaining a Better Understanding of Parasite Resistance in Sheep”
Of the internal parasites that infect sheep, the gastrointestinal nematode (GIN) Haemonchus contortus arguably represents the greatest concern. H. contortus is widespread and an incredibly pathogenic parasite. The high prevalence of anthelmintic drug resistance in H. contortus populations poses a significant threat to affected herds. Although resistance to GIN has been shown to be a moderately heritable (h2 = 0.17 to 0.46) trait in sheep, little is understood about the genetic mechanisms responsible.
To better understand the genetic differences between resistant and susceptible animals, a genome-wide association study (GWAS) was conducted. Fecal egg count estimated breeding values (FEC EBV) were determined for 641 Katahdin sheep to estimate genetic potential for resistance. From these animals, 40 rams were selected from the top and bottom 10% to represent the most divergent phenotypes. Samples were genotyped by AxiomTM Ovine Genotyping Array consisting of 51,572 single nucleotide polymorphisms (SNPs).
Statistical analyses were conducted through linear regression and single-locus mixed-model approaches with genome-wide significance defined by a Bonferroni correction for multiple testing. GWAS identified loci that were significantly associated with FEC EBV on five chromosomes. From this preliminary study, we suggest a potential role for the gene DIS3L2 in gastrointestinal nematode resistance in Katahdin sheep.
Gabrielle Becker is a master’s student in Animal & Vet Science under Dr. Brenda Murdoch.