Evolution of feeding preference in the Calliphoridae family

Abstract

Since most phenotypic changes between closely related species can be attributed to regulatory variation, cross-species comparison of gene expression is a powerful tool to understand the transcriptome evolution and the architecture of regulatory networks. Hence, the comparative analysis among species with contrasting feeding habits is an excellent opportunity to study the evolution of parasitism. Owing to the recent advances in sequencing technologies it is now possible to pursue genome-wide analysis for non-model species in a phylogenetic context. The Calliphoridae family is particularly interesting for such a study as it is characterized by a range of feeding habits of its species. Another interesting aspect of this family, which makes it an ideal model for the evolution of a complex behavior, is the appearance of obligate parasitism in at least three independent events in its evolutionary history. In the most parsimonious scenario, the generalist lifestyle would be the ancestral state, and this flexibility has allowed these flies to explore new niches. Here, I propose to characterize the transcriptomes of five Calliphoridae species (sequence and expression levels) by using RNAseq. The species chosen for this study represent the lineages where the parasitism have appeared in two independent events.The data that will be gathered will allow the investigation of adaptive changes across different species/lifestyles, allowing the discovery of important genes and gene networks that are involved in the expression of the unique phenotype of each species. In a broader scale, it will be an important step towards understanding the structure and function of genomes, such as the molecular processes underlying the adaptation to new environments and speciation. (AU)