Ascidians for cell and developmental biology 

Welcome to the Tunicates module! This course is destined both for Schmid Training Course students, as well as any student interested in this organism, and is a co-creation by Sébastien Darras, CNRS researcher at the Observatoire Océanologique de Banyuls-sur-Mer, Stefano Tiozzo, CNRS researcher at the Institut de la Mer de Villefranche-sur-Mer, and Jean-Philippe Chambon, Associate Professor at Sorbonne Université. In this module, you will discover our closest invertebrate relatives: the tunicates. 

The first two chapters present the general characteristics of tunicates and their phylogeny. In Chapter 3, we describe in greater detail the developmental biology of one class of tunicates: the ascidians. In Chapter 4 you will find a short animation for key experimental techniques used to study ascidians. The use of ascidians as experimental models in cell and developmental biology will be developed during the Schmidt Training Course. Finally, in Chapter 5, you will have a glimpse of the lively and friendly Tunicate scientific community.

Chapter 1. What are tunicates?  

Stefano will show you what tunicates look like, and give an overlook on their biology, life cycles, and anatomy. Tunicates are an extremely diverse group but have a great number of common features as well.


Chapter 2. History and phylogeny of tunicates  

Sébastien will take you on a short journey through tunicates’ phylogenetic relationships… which should help you understand why it is difficult to determine the correct relationships between different species.

Chapter 3. What are ascidians? 

Ascidians are the most abundant tunicate group, and are also the most studied. In this chapter, you will discover their life cycle, anatomy, and development in detail. First, Jean-Philippe will describe solitary ascidians, and then Stefano will focus on colonial ascidians. 

3.1 Solitary ascidians  



3.2 Colonial ascidians 




Chapter 4. Use of ascidians in biological research 

Ascidians are great models for experimental biology and functional genomics. Some techniques are common to other organisms presented in DigitalMarine (such as in the Annelids and Amphioxus modules), while others are specific to ascidians. You can see in the following animation how exogenous molecules (plasmid DNA, mRNA, proteins…) can be introduced into the developing embryo using two distinct methods: microinjection and electroporation. More experimental approaches, scientific questions and hypotheses, key achievements, and more will be presented during the Schmidt Training Course.  


Chapter 5: The Tunicate Community 

The tunicate scientific community is relatively small but very friendly. Every two years, researchers from different fields (ecology, evolution, taxonomy, cell biology, developmental biology…) gather for the International Tunicate Meeting. Several highly-recognized scientists of the community were interviewed for DigitalMarine during the 2019 International Tunicate Meeting in Villefranche-sur-mer, France. 


Interview of Hiroki Nishida  Download here (.pdf)


The Tunicate portal is an entry point to labs and resources in the Tunicate community: http://tunicate-portal.org/