Associations of Variation in mtDNA With Feed Efficiency in Beef Cattle and the Evaluation of Transcriptomic Changes in Fetal Kidney Due to Hydrallantois

Authors

Lauren Elizabeth Seier, University of Nebraska-LincolnFollow

First Advisor

Jessica L. Petersen

Committee Members

Dustin T. Yates, Kristi L. Montooth

Date of this Version

8-2025

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Animal Science

Under the supervision of Professor Jessica L. Petersen

Lincoln, Nebraska, August 2025

Comments

Copyright 2025, Lauren Elizabeth Seier. Used by permission

Abstract

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 feed intake. These findings support the hypothesis that variation in the mitochondrial genome may influence feed efficiency and economically important traits, which could aid in genomic selection and breeding decisions.

Project 2 utilized transcriptomic data to investigate the molecular mechanisms influencing or resulting from abnormal allantoic fluid accumulation during late gestation. Serum chemistry and histopathology reports of the affected fetuses indicated renal dysfunction. Fetal kidney tissue was used to investigate differential gene expression in affected and unaffected calves, and to identify dysregulated biological pathways. Analysis of enriched pathways revealed that differentially expressed genes (DEGs) were involved in vasculature development, renal ion transport, and membrane signaling, which may contribute to the accumulation of allantoic fluid. CALRC, a gene involved in calcium ion binding, was significantly upregulated in affected fetuses and has the potential to disrupt fetal fluid homeostasis. These findings underscore the importance of RNA sequencing in elucidating the molecular mechanisms underlying complex diseases and identifying functional disruptions.

Advisor: Jessica L. Petersen