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| Author(s): |
Pedro Mariano Martins
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2024-04-19 |
| Examining board members: |
Tatiana Teixeira Torres;
Marco Antonio Tonus Marinho;
Mariana Freitas Nery
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| Advisor: | Tatiana Teixeira Torres |
| Abstract | |
Blowflies (Diptera, Calliphoridae) are a diverse family of flies whose larvae feed on animal tissues. Depending on whether the animals they feed from are alive or dead, they can be classified as either parasites or necrophages, respectively. It is assumed that the parasitic behavior emerged convergently within Calliphoridae. However, it is unknown whether this happened under the control of the same genetic framework or not. We tackled this question with several approaches: i) comparing the expression profile of parasitic species (Cochliomyia hominivorax and Chrysomya bezziana) to their necrophagous sisters (Cochliomyia macellaria and Chrysomya megacephala, respectively); ii) identifying genes whose expression levels correlated with a substrate preference; iii) comparing the rate of evolution of genes in parasitic lineages with the rest of the family; iv) identifying genes that have specific codons evolving under positive selection; v) finding non-coding regions (and nearby genes) that are evolving faster in Co. hominivorax compared to other species; and, iv) testing the feeding preference of mutants for a candidate gene. All the analyses yielded promising candidates, yet there were few of them that could be intuitively linked to the feeding phenotypes. Most of the genes we identified were usually represented within the results for just one parasite, rather than both. Usually, most genes were development-related, what might be explained by the fact the distinct behaviors are displayed by larvae, thereby overlapping, and interacting with development. However, by identifying the biological functions and processes with which the gene sets are involved and subsequently overlapping these results, some noteworthy functions have emerged. As expected for such a complex behavior, it appears that the convergence observed at the ecological level is being influenced by distinct genes that share the same functions and pathways (mostly developmental), rather than the same specific genes. (AU) | |
| FAPESP's process: | 21/01641-6 - Natural Selection on Blowfly Genomes and Transcriptomes |
| Grantee: | Pedro Mariano Martins |
| Support Opportunities: | Scholarships in Brazil - Master |