Projeto de pesquisa

Colonial development has evolved several times in the tunicates. Modular developmental mechanisms of the botryllids, a derived clade of colonial styelid ascidians (Ascidiaceae: Tunicata), present cyclic and synchronic budding, regulated by circulatory stem cells in their vascular system and processes of programmed cell death (PCD). For my doctorate, I propose to study mechanisms of modular coordination by budding tissues and cells in Symplegma, the sister group of botryllids, and to evaluate the effects of environmental heterogeneity on colonial organization. Previous work showed modular effects on colony development after bud removal, therefore we hypothesize that buds may act as stem cell sources and/or regulate PCD during cyclic budding. To identify modules affecting mechanisms of intercommunication of individuals that compose the colony (modules), I will surgically remove early buds at different stages and test for whole colony effects of development. Once affecting bud stages are identified, I plan to ablate specific tissues and organs in those buds to identify the source of modular coordination. Next, I will characterize circulatory blood cell morphology and expression of molecular markers specific to stem cells and hematopoietic linages during colony development of Symplegma. Finally, I will evaluate the effects of exogenous and endogenous factors on the overall aggregation of colonies. These studies aim to provide further understanding on the developmental and evolutionary mechanisms involved in colonial life histories of ascidians.