In tunicates, the capacity of budding, and therefore re-growing of clonal copies of the original individual (zooid), occurs through different mechanisms of interaction between non-homologous epithelial tissues and/or putative stem cells circulating in the bloodstream. Our driving hypothesis is that emergence of non-embryonic development (NED) relies on homologous genetic modules repeatedly co-opted and rewired in different species regardless of the nature of cells and tissues triggering budding/regeneration. To explore the similarities and differences in the cellular and molecular mechanisms underlying different forms of NED, and to infer how these mechanisms have been gained and lost during evolution, we use keep study closely related suitable models belonging to the Styeliadae family: Botryllus schlosseri and Polyandrocarpa zorritensis. We test our hypothesis by approaching at two different levels: (A) by a comparison of the transcriptome profiles of the budding tissues at different developmental steps across the two different species, and (B) by exploring and functionally dissecting the mechanisms of budding focusing on Botryllus schlosseri, where protocols and functional approaches have been already developed.