MSc Student
Advisor: Roger Revilla-i-Domingo

Department of Neuroscience and Developmental Biology
University of Vienna

Abstract

Two of the main features characterising the metazoan phylum are multicellularity and the ability to form multiple specified cell types by gene expression-driven cell differentiation. Despite their great importance it is still unclear how these major traits have emerged exactly during the evolution of animals. The long accepted classical view was strongly shaped by the Gastraea Hypothesis of Ernst Haeckel (1874) and comprises the idea that multicellularity predated the emergence of cell differentiation at the origin of the animal phylum. However, more recent investigations found that many of the closest unicellular relatives of metazoans show a complex life cycle that includes diverse cell morphologies and functions. Respective gene regulatory networks appear surprisingly elaborated and involve homologs of genes that are known to play a role in metazoan cell differentiation. These findings indicate that cell differentiation in multicellular animals might be based on gene regulatory modules that have already been involved in the temporal cell differentiation of closely related unicellulars.

In order to investigate the origin of animal cell differentiation it is necessary to compare basal metazoan representatives and closely related unicellular outgroups. Our research group aims to apply similar experimental approaches on the unicellular species Abeoforma whisleri (Marshall, 2008 - Ichthyosporea) and Capsaspora owczarzaki (Hertel, Bayne & Loker, 2008 - Filasterea) as well as on the marine sponge Suberites domuncula (Olivi, 1792). By doing so we will be able to obtain comparable data on gene regulatory modules involved in cell differentiation directly. In the framework of my Master’s project I will work on single cell profiling data of Suberites domuncula. By finding cell type-specific marker genes and using those to perform HCR RNA FISH in sponge regenerates I will validate the bioinformatic clustering and uncover the cellular identity of clusters. Furthermore, I will initiate our work on single nuclei profiling of Abeoforma and Capsaspora, in cooperation with the Multicellgenome Lab of Inaki Ruiz-Trillo in Barcelona (Institut de Biologia Evolutiva, CSIC-UPF).