Final Report Summary - MULTICELLGENOME (A comparative genomic analysis into the origin of metazoan multicellularity)
The origin of multicellular animals from their protistan ancestors is one of the most important evolutionary transitions in life’s history. The main goal of the project was to provide insights into this question by the use of comparative genomics and molecular techniques in two close unicellular relatives of Metazoa: the filasterean Capsaspora owczarzaki and the ichthyosporean Sphaeroforma arctica. The project have sequenced, annotated and analyzed the first genome sequence of a filasterean, Capsaspora owczarzaki, and the first genome sequence of ichthyosporeans (Sphaeroforma arctica and Creolimax fragrantissima). Comparisons of the genome of Capsaspora owczarzaki with those of metazoans have dramatically changed our understanding of animal origins, by showing that the unicellular ancestor of animals had a much more complex repertoire of genes involved in multicellularity than previously thought-including genes involved in cell adhesion, cell signaling and cell communication. Most of those genes were previously thought to be specific to animals. These findings suggest that co-option of ancestral genes played an important role in animal origins. Moreover, during the project we have developed for the first time transgenesis tools among unicellular relatives of Metazoa. These methodologies provide an invaluable tool to directly analyze in the future what are those genes involved in multicellularity doing in the unicellular taxa to understand how they were co-opted. Thus, the combination of genomic analyses and the development of new methodologies done during this project provides important insights into the original of animals, as well as provides the basis for future research avenues.