Evolution of the control pathways of tissue development in holometabolous insects

Author(s)

Raquel Dietsche Monfardini

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2018-12-10

Examining board members

Tatiana Teixeira Torres; Denise Selivon Scheepmaker; Henrique Marques Barbosa de Souza

• Advisor: Tatiana Teixeira Torres; Álisson Marques de Miranda Cabral Gontijo

Abstract

The metamorphosis delay due to tissue damage in imaginal discs is a control mechanism of larval development observed in several species of insects. This mechanism is regulated by the Ilp8 protein in Drosophila melanogaster, but there are no studies about how the ilp8 gene evolved, and how this mechanism is regulated in other insects. The objective of this project is to understand how the metamorphosis delay evolved as a control mechanism of tissue development. The first step was to determine which insect species have homologs of the ilp8 gene of D. melanogaster. By searching publicly available databases it was possible to find this gene in the main dipteran groups, suggesting that it is an inovation of the Brachycera group. To understand the evolution of the relationship between ilp8 and the tissue-damage-dependent delay in metamorphosis, we performed tissue damage assays associated with RNA-seq in species with (D. melanogaster, Chrysomya megacephala and Hermetia illucens) or without (Manduca sexta) ilp8 homologues. With this approach it was possible to study the global expression variation in response to the tissue damage. Although the four species studied delayed metamorphosis upon treatment with the DNA-damaging agent EMS, only D. melanogaster showed a detectable increase of the ilp8 expression in the damaged larvae. These results indicate that the metamorphosis-delay function of the ilp8 gene evolved relatively late during its evolution, when Drosophila differentiated from other Brachycera (AU)

• FAPESP's process: 15/20183-8 - Evolution of the control pathways of tissue development in Diptera
• Grantee: Raquel Dietsche Monfardini
• Support Opportunities: Scholarships in Brazil - Master