Thesis
Functional analyses of fat signaling genes during exaggerated horn growth in the Asian rhinoceros beetle Trypoxylus dichotomus (Coleoptera: scarabaeidae)
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/100886
Abstract
Most morphological traits grow in relative proportion to total body size. Yet, some traits exhibit exaggerated growth; that is, they grow faster and larger during development and scale to extreme proportion relative to body size. The genetic mechanisms underlying exaggerated trait formation are not well known. Trait size usually covaries with body size because both respond to common whole-body circulating growth signals. The Fat signaling pathway is a potential link between the whole-body circulating signals that regulate growth and tissue-specific exaggerated trait growth. Fat signaling is a highly conserved signaling pathway that regulates the growth and polarity of developing tissues in animals. Here, I used RNAi to perform functional analysis of Fat signaling pathway genes during exaggerated head horn growth in the Asian rhinoceros beetle (Trypoxylus dichotomus). RNAi knockdown of the gene fat reduces the length and increases the width of the head and prothoracic horns, and all of the appendages. Also, I used electron microscopy to investigate head horn epithelial cell shape and found evidence to support the hypothesis that fat regulates the shape of individual cells in developing tissues. RNAi knockdown of the gene scalloped results in ‘scalloped’ wing margins, abnormal antero-lateral outgrowths of the prothoracic tergum, and a high incidence of incomplete eclosion from the pupal stadium, but has no apparent effect on the growth of the head or prothoracic horns. RNAi knockdown of yorkie results in death, or a pupal/larval intermediate phenotype and severe undergrowth of legs. Importantly, this study provides evidence that the Fat signaling pathway genes fat, scalloped, and yorkie are not involved in regulating exaggerated head or prothoracic horn growth in T. dichotomus.
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Details
- Title
- Functional analyses of fat signaling genes during exaggerated horn growth in the Asian rhinoceros beetle Trypoxylus dichotomus (Coleoptera: scarabaeidae)
- Creators
- James Alexander Hust
- Contributors
- Laura C. Lavine (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525198801842
- Language
- English
- Resource Type
- Thesis