Projeto de pesquisa

Coloniality evolved numerous times within the metazoans, leading to many convergent ecological and developmental features that differ from those associated with a solitary lifestyle. Colonial animals - those having the capacity to asexually reproduce and remain connected - not only grow and occupy space differently from their solitary relatives, but they also show extensive regeneration abilities, have unique allorecognition systems and display systematized senescence. Many of these features are linked to the fact that colonial species posses tissues besides the germline that remain pluripotent. In order to determine the origins of coloniality and the traits associated with the colonial life style, I plan to examine the evolutionary origins and functions of these pluripotent cells. Along with collaborators, I will examine stem cells in the vascular system of ascidians (subphylum Tunicata), which are essential for asexual budding and regeneration in colonial species. We will focus on the family Styelidae since they exhibit broad variation in the degree of coalescence, i.e. some are solitary, some clone and remain only loosely connected, and others are highly integrated, sharing a tunic and vasculature. We will compare stem cell populations in styelids to test the hypothesis that more highly coalesced species have more abundant and more diverse stem cell types. We will reconstruct the phylogenetic origins of the stem cell types and degree of coalescence within the styelids. We will focus on transcriptome-based tree reconstruction. I will determine if abundances of particular stem cell types correlates to life history phases (i.e. sexually reproducing vs. asexually proliferating). Results from this study will be essential to our understanding of how blood stem cells function and how they originated and diversified. In addition, I plan to explore the environmental factors that favor the evolution of coloniality along the Southweste