The impact of variation in the Toll-like receptor 3 gene on epizootic hemorrhagic disease in Illinois white-tailed deer (Odocoileus virginianus)

Wessels, Jacob E.

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https://hdl.handle.net/2142/113336 Copy

Description

Title

The impact of variation in the Toll-like receptor 3 gene on epizootic hemorrhagic disease in Illinois white-tailed deer (Odocoileus virginianus)

Author(s)

Wessels, Jacob E.

Issue Date

2021-07-21

Director of Research (if dissertation) or Advisor (if thesis)

Roca, Alfred L

Committee Member(s)

• Mateus-Pinilla, Nohra E
• Novakofski, Jan E

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• white-tailed deer
• epizootic hemorrhagic disease
• TLR3
• gene
• toll-like receptors
• genetics
• EHD, disease
• outbreaks
• genetic variation
• polymorphism

Abstract

Epizootic hemorrhagic disease (EHD) is of concern to hunters, wildlife managers, and state agencies as it leads to death in white-tailed deer (Odocoileus virginianus). The EHD virus (EHDV) is a double-stranded (ds) RNA virus and is transmitted by midges of the genus Culicoides. Toll-like receptors (TLRs) are part of the innate immune system and detect various types of pathogens upon infection. One of the Toll-like receptors, TLR3, recognizes pathogen-associated molecular patterns in dsRNA viruses, thus playing a key role in immune detection and response to EHDV. In this thesis, I study genetic variation within TLR3 and its association with EHD in white-tailed deer from Illinois. The entire coding region of the TLR3 gene (2715 base pairs encoding 905 amino acids) was sequenced in 84 white-tailed deer. Twenty-six deer with an EHD positive result and 58 negative control deer were analyzed. I detected 77 SNPs and identified 85 haplotypes. Of these 77 SNPs, 45 were synonymous mutations and 32 were nonsynonymous mutations. Two non-synonymous SNPs within TLR3 were significantly associated with EHD in Illinois white-tailed deer. Phenylalanine (F) at codon position 59 was detected more frequently than leucine (L) (OR = 8.69, p = 0.0340, Fisher’s exact test) in EHD negative deer as opposed to EHD positive deer. Phenylalanine (F) at codon 116 was also detected more frequently than serine (S) (OR = 9.29, p = 0.0403, Fisher’s exact test) in EHD negative deer as opposed to EHD positive deer. Codons 59 and 116 were found to be in linkage disequilibrium; however, protein effect analysis tests predicted an impact on protein structure when analyzing SNPs found at both codons 59 and 116. Deer that tested positive for EHD have a significant reduction in a substitution that encodes phenylalanine (F) at codons 59 and/or 116 within the TLR3 gene. Understanding associations between TLR3 polymorphisms and EHD may provide additional insights into the role of host genetics on outbreaks of EHD in deer, which may allow wildlife agencies to better predict the severity of outbreaks.

Graduation Semester

2021-08

Type of Resource

Thesis

Permalink

http://hdl.handle.net/2142/113336

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Copyright 2021 Jacob Wessels

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