Evolution of olfactory receptors, CAZymes and peptidases gene families in blowflies

Abstract

Olfactory chemoreceptors and digestive enzymes play essential roles in the nutrition of an organism and, consequently, in its survival. The first ones act on locating and selecting food by responding to environmental chemical cues, and the latter, on making nutrients effectively available for absorption and posterior usage. Changes in the repertoire of both groups are suggested to have led to the differentiation of feeding habits among Calliphoridae (Diptera) species. Those can feed on decaying organic matter, strictly on host living tissues or on both living and dead host tissues, by what they are generally classified as saprophagous, obligate parasites or facultative parasites, respectively. Interestingly, within some calliphorid genera, there are both saprophagous and parasite species, which make them excellent models for studying the genetic drivers of trophic specialization. In this context, the present project aims to investigate the relationship between the evolution of olfactory chemoreceptors and digestive enzymes with the evolution of feeding habits in Calliphoridae. For this purpose, gene families of olfactory chemosensors, carbohydrases (CAZymes) and peptidases will be characterized through the phylogeny of blowflies, accounting for their composition, expansion/contraction events and expression. Moreover, the expression of the digestive enzymes will be evaluated in the digestive tract of two species with contrasting feeding habits, in order to identify possible differences in the gene expression that correlates with their different diet. (AU)