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| Author(s): |
Nancy França Lo Man Hung
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2024-07-02 |
| Examining board members: |
Tatiana Teixeira Torres;
Rodrigo Nunes da Fonseca;
Ricardo Pinto da Rocha;
Lina Maria Almeida Silva
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| Advisor: | Tatiana Teixeira Torres; Prashant Pradeep Sharma |
| Abstract | |
This thesis delves into the development and evolution of spinnerets, a crucial structure for spiders. Beginning with an extensive literature review, we explore the morphology, classification, development, and prevailing hypotheses on spinneret origins. A significant milestone was achieved through the sequencing of the transcriptome of a novel Hahniidae spider species from Sao Paulo, Brazil, contributing to our understanding of spider diversity. Integrating this transcriptome data with 215 others from various species, we constructed a robust phylogenetic framework, offering deeper insights into the evolutionary relationships within the marronoid clade. Contrary to recent portrayals of monophyly, our study reveals a paraphyletic marronoid clade, highlighting the complexity of its evolutionary history and challenging previous assumptions. Further investigation delves into the molecular rate of evolution of candidate genes, demonstrating site-specific positive selection in the Araneae lineage, and discussing their possible involvement on spinneret ontogeny. Additionally, through maternal RNA interference, we induced the development of spiders with ten legs, shedding light on the functionality of ectopic legs and the implications of gene function for the evolution of appendix morphology. Practical comparisons of RNA extraction methods highlighted critical factors influencing downstream analyses. Lastly, an unprecedented investigation into spinneret regeneration unveiled complex cellular pathways and connections to gene expression of toxin genes, with potential implications for therapeutic and regenerative medicine. This thesis contributes significant advancements in understanding spinneret development, spider evolution, and spinneret regeneration, contributing to both fundamental knowledge and potential practical applications. (AU) | |
| FAPESP's process: | 17/19616-2 - Evolution and development of spiders' spinnerets (Arachnida: Araneae) |
| Grantee: | Nancy França Lo Man Hung |
| Support Opportunities: | Scholarships in Brazil - Doctorate |