Sistemática e Evolução - Comunicações orais

The innate immune system is of central importance in the prevention of deleterious effects in infection response. The adaptive immune system offers long-term protection and the innate immune system is the first line of defense against pathogens. While vertebrate immune systems are relatively well-characterized, immune response in invertebrates is only known for a few model species. Therefore, strategies used to evade pathogens and factors driving their evolution are poorly understood. Transitions to parasitic and epibiotic lifestyles are known to result in adaptations that allow organisms to live in close association with their hosts. Moreover, such transitions expose the parasite, the epibiont and their respective hosts to a new set of pathogens. Hence, it is expected that these organisms present adaptations related to the immune response due to such transitions. Barnacles are members of the phylum Arthropoda with around 1,200 extant species distributed among two lineages. Members of Rhizocephala are common parasites of other crustaceans. Epibiotic species are distributed within Thoracica and represent independent transitions from a non-epibiotic to an epibiotic lifestyle. This unique distribution of parasitism and epibiosis allows the study of adaptations related to the immune response against pathogens in response to transitions. The present study aims to screen for well-known components of the innate immune response in barnacles, as well as to understand patterns of evolution driving the diversification of gene families with immune function using publicly available transcriptomes and genomes. We will also sequence one genome of an epibiotic barnacle.  At present, we found genes belonging to the following families: toll-like transmembrane receptors (TLRs), RIG-I-like receptors (RLRs), Interferon Regulatory Factors (IRFs) and Vago in barnacles. We will further investigate patterns of evolution by looking for signs of positive selection, relaxed selection and expansion or contraction within epibiotic or parasitic lineages.