The effects of stress on avian gene expression and microbiomes

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Daniel J Newhouse (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Organisms must cope with stressors throughout their lifetime. Stressors are broad and come from both intrinsic and extrinsic sources. In this era of rapid global change , exposure to stressors will become more unpredictable and frequent. Thus , it is imperative we begin to understand how organisms respond to these stimuli. Birds are useful models to investigate responses to stress , as they are a diverse taxonomic group encompassing both well studied ecological and laboratory models. Here , I use several bird species and sources of stress to investigate how birds respond from a transcriptomic and microbiome perspective. The first two chapters investigate how infection and androgens impact gene expression of the avian immune system. In Chapter 1 , I explore the avian immune transcriptomic response to West Nile virus , a common avian pathogen that has had devastating effects on birds since its emergence in North America. In Chapter 2 , I test the Immunocompetence Handicap Hypothesis , which states that androgen-dependent sexually selected traits are costly to produce because androgens are simultaneously immunosuppressive. I used previously published transcriptome data and found support for the hypothesis. In Chapters 3 & 4 , I turn my focus to early-life stress and white-throated sparrows (WTSPs). WTSPs exhibit two stable alternative parental care strategies , biparental care and female-biased parental care. In Chapter 3 , I show that female-biased care induces a transcriptomic stress response in nestlings. In Chapter 4 , I investigate the microbiome of WTSP nestlings and find no differences between individuals raised under the different parental care strategies. However , I do find some evidence of host genetic control of the microbiome. Overall , I have begun to explore how birds cope with various stressors , including infection , androgen induced immunosuppression , and developmental stress. Through primarily gene expression approaches , I uncover the molecular pathways affected by these stimuli. Each chapter will set the stage for future integrative work to explore organismal responses to their environment.

Additional Information

Publication

Dissertation

Language: English

Date: 2019

Keywords

genomics, transcriptomics, immune

Subjects

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