Please use this identifier to cite or link to this item: https://scholarbank.nus.edu.sg/handle/10635/156064
Title: UNCOVERING THE EVOLUTION AND DEVELOPMENT OF A NOVEL ABDOMINAL APPENDAGE IN BLACK SCAVENGER FLIES (SEPSIDAE: DIPTERA)
Authors: GOWRI D/O RAJARATNAM
Keywords: evolution, development, novelty, Diptera, CRISPR/Cas9, phylogenomics
Issue Date: 24-Jan-2019
Citation: GOWRI D/O RAJARATNAM (2019-01-24). UNCOVERING THE EVOLUTION AND DEVELOPMENT OF A NOVEL ABDOMINAL APPENDAGE IN BLACK SCAVENGER FLIES (SEPSIDAE: DIPTERA). ScholarBank@NUS Repository.
Abstract: I explore the evolution and development of a novelty in sepsid flies where males have recently evolved an elaborate brush-like appendage on the fourth abdominal segment that varies in shape and size across the family. A comparative analysis showed that male sepsids pay for more ornate 4th sternite brushes by reducing their body size and extending pupal development. I then trace the evolution of the 4th sternite brush, using a phylogenomic analysis, and show that it evolved once, was lost multiple times and reacquired in at least two species. Next, I use an optimized CRISPR/Cas9 gene editing system to test the role of candidate genes in its development in two species with morphologically distinct sternite brushes: Themira biloba and Perochaeta dikowi. I find that doublesex and abdominal-A have been co-opted into the GRN underlying 4th sternite brush development in both species. In T. biloba, extradenticle and Distal-less are additionally co-opted while there was no evidence for the involvement of Distal-less in P. dikowi, suggesting that its role in the GRN was either lost in P.dikowi or gained in T.biloba. Surprisingly, I also demonstrate a potentially unique function of doublesex and Distal-less in patterning the adult abdominal epidermis in T. biloba.
URI: https://scholarbank.nus.edu.sg/handle/10635/156064
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