Document Type
Thesis
Date of Award
2025
Degree Name
Master of Science (MS)
Department
Biology
First Advisor
Bernard W. M. BW Wone
Abstract
The adaptation of small birds to cold environments involves mechanisms for both heat conservation and heat generation. While minimizing heat loss reduces the energy needed to maintain body temperature, thermogenesis remains essential. Shivering and non-shivering thermogenesis (NST) are two likely mechanisms supporting cold adaptation in small avian species. Although sarcolipin (SLN) aids NST in small mammals, studies in birds such as Dark- eyed Juncos have shown no increase or even a decrease in SLN expression during cold exposure, suggesting limited involvement. This may reflect biological differences or limitations of mRNA- focused sequencing, which excludes long non-coding RNAs (lncRNAs) capable of encoding micropeptides. Micropeptides such as myoregulin (MLN), dwarf open reading frame (DWORF), phospholamban (PLN), and mitochondrial ORF of the 12S rRNA type-c (MOTs-c) have roles in NST and other physiological processes including cell signaling, apoptosis, muscle remodeling, protein degradation, stress response, and metabolic regulation. This study aimed to elucidate the NST response in the Black-capped Chickadee (Poecile atricapillus), a species with high mitochondrial density in flight muscles, critical for shivering, metabolic adjustments, and potentially NST. Using lncRNA-Seq to capture both lncRNAs and mRNAs, we identified 2,480 mRNAs and 257 lncRNAs differentially expressed between winter and summer. Of these, 117 lncRNAs and 943 mRNAs were upregulated in winter, while 140 lncRNAs and 1,537 mRNAs were downregulated. Additionally, 964 novel lncRNAs were discovered, with ongoing functional annotation using BLAST for sequence homology predictions. Several mRNAs related to extracellular matrix remodeling (e.g., PXDN, MXRA5, MMP2, COL28A1, COL4A1) were reduced in winter, suggesting decreased tissue turnover during cold months. Conversely, winter-upregulated mRNAs likely support cold adaptation via stress response and metabolic reprogramming. LncRNAs also exhibited strong seasonal expression patterns. ESRRG-OT1 and rna_NC_024867_1_1124_2716-OT2 were markedly decreased in winter, potentially reflecting summer-linked reproductive or growth processes, while other lncRNAs increased in winter, likely functioning in thermoregulation, energy metabolism, or immune modulation. KEGG analysis identified 20 significantly enriched pathways, including fatty acid biosynthesis, ECM-receptor interaction, and cytokine signaling. These findings suggest that lncRNA-encoded micropeptides may contribute to thermogenic processes in small birds, although further functional validation is required.
Subject Categories
Biology
Keywords
Cold adaptation, Non-shivering thermogenesis (NST), Long non-coding RNAs (lncRNAs), Micropeptides, Black-capped Chickadee (Poecile atricapillus), Mitochondrial density, Extracellular matrix remodeling, KEGG pathway enrichment
Number of Pages
51
Publisher
University of South Dakota
Recommended Citation
Chand, Sweta, "Elucidating the non-shivering thermogenesis response in the Black-capped chickadee (Poecile atricapillus)" (2025). Dissertations and Theses. 365.
https://red.library.usd.edu/diss-thesis/365