Evolution of Nervous systems

The emergence and diversification of bilateral animals are amongst the most important transitions in the history of life on our planet. However, although numerous labs are currently working on selected questions of genomic and morphological evolution, no interdisciplinary networks are currently in operation. As a result, many critically positioned animal groups have not been analysed and a comprehensive mapping of their genomes and tissue systems remains elusive. Our group research projects are focused on elucidating the evolutionary and developmental origins of organismal and genomic complexity. A specific aim is to provide answers to the questions: How did complex body plans arise in evolutionary time? How are complex body plans “encoded” in the genome? As the first step, we have focused our efforts on the understanding of the earliest stages in bilaterian evolution, probing the most elusive organisation of the genomes and microscopic anatomy in basally branching taxa, which are currently assembled in a clade named Xenacoelomorpha. This enigmatic phylum is composed of three major taxa: acoel flatworms, nemertodermatids, and xenoturbellids. Interestingly, the constituent species of this clade have an enormously varied set of morphologies; not just the obvious external features but also their tissues present a high degree of constructional variation. This interesting diversity of morphologies (a clear example being the nervous system, with animals showing different degrees of compaction) provides a unique system in which to address outstanding questions regarding the parallel evolution of genomes, proteomes, and the many morphological characters encoded by them. Our team’s major long-term goal is to employ multidisciplinary approaches to decipher the morphological and genomic bases of the organisation and physiological roles of these organ systems. Having access to high quality genome and transcriptomic data is key for advances in the field (something that is clearly missing for this group of animals). Complementary technologies have been brought to the analysis of xenacoelomroph morphologies and developmental process.

Members

Pere Martínez

I graduated in Chemistry (Biochemistry and Molecular Biology) in 1982 from the “Universitat Autònoma de Barcelona”, where I also obtained my PhD (in 1990). During my PhD I focused my attention on the expression of

histone variants during mice and rat cerebral cortex development. This Project was finished in two American laboratories, the laboratory of Prof. Ronald Evans (Salk Institute) and Prof. Leroy Hood (California Institute of Technology; Caltech). I did a postdoctoral stay at the Caltech), working on sea urchin embryology at the laboratory of Prof. Eric H. Davidson. A period of my stay I was a senior fellow of the Stowers Foundation. I returned to Spain as a “Becario de reincorporación”, working in the laboratory of Prof. Carlos Martinez-Alonso, at the “Centro Nacional de Biotecnología” (Madrid, Spain), where I developed a Project on the impact of cell death in vertebrate morphogenesis. My first permanent position was as Associate Professor in the Faculty of Medicine at the University of Bergen (Norway), where I developed new Projects on echinoderm embryology and regeneration. There I was also professor of Histology and Cell Biology. Currently I am an ICREA Research Professor at the Universitat de Barcelona, Departament de Genètica, a position that I hold since the year 2003. The area of my research is the Evolution of Developmental Mechanisms. At the Universitat de Barcelona I was also the head of the "Genetics" Doctoral Program.

My research projects have lead to the production of 50 papers plus one extensive chapter on Echinodermata (for the first Invertebrate Evo-Devo manual, in 6 volumes, published in the year 2016 by Springer Verlag) and another on “Xenacoelomorpha Nervous Systems” (for Oxford University Press, 2017) . These papers have provided me with a well-respected position in the field of Evo-Devo, which is reflected in the fact that I am member of the editorial board of Journal of Experimental Biology and Frontiers in Evo Devo, two reference journals in the field. Moreover I have been acting, regularly, as referee for the National Science Foundation, the BBSRC (UK), the French and German Research Councils, and ANECA. I have been also a member of the “Ramon y Cajal” Grant panels.

I obtained Grants as Principal Investigator while in Norway and Spain (regularly, without any temporal gap). I had two EU major Grants, one “Network of Excellence” and one “Marie Curie Early training Network”. I also received small travelling Grants from the EU, in the programmes “EMBO Short” and “Assemble”, but also from the Swedish Royal Academy (several times). I was a Visiting Scholar at the University California Sand Diego (UCSD). I have teaching experience; besides my involvement in undergraduate training in Norway (Histology and Cell Biology), the last years I am teaching a Master’s course on “Gene Regulatory Networks” at the U.B. I am giving this course also at the University of Fribourg (Switzerland), as an invited professor. During the years in Barcelona I have produced 5 PhDs and 3 Masters. one more PhDs and a Master are under way. We had, at different periods, students visiting from many different countries, completing their projects or helping us with ours. We also had two postdocs in the lab working in acoel development. Recently we developed transcriptomic tools applied to echinoderm and acoel regeneration. My activities rely on international collaborations. I participated in the sequencing and annotation of the sea urchin genome (a Science paper in 2006), and I am currently involved in a similar Project involving 6 genomes of different members of the phylum Xenacoelomorpha. Moreover, I gave several invited talks at professional meetings (or in institutions) both in Europe and USA. Other details of my CV can be read in the following paragraphs. Our group single-handled the incorporation of acoel models, and the development of tools, to the range of modern EvoDevo systems. We are nowadays the group leader in this field of study. Now I have been awarded a H2020 COST (Coordinated) Grant to investigate stem cells and regeneration in marine invertebrates.

Brenda Gavilán, PhD student

During my PhD I had the chance to study our reference species from different approaches: phylogenetic, molecular, and also, using electron transmission techniques. Always focusing on the evolution of the formation and the function of the organs, and more specially of the nervous system.

Specifically, I am currently using Transmission Electron Microscopy serial sections (system) of the juvenile of our reference species, the acoel Symsagittifera roscoffensis, in collaboration with Prof. Hartenstein in UCLA. This approach allows us to analyze in detail the structure and 3D organization of the different cell types and how they connect with each other and, very specially, with the nervous system. This is particularly challenging in this group of animals, as different cell types appear intermingled with highly folded membranes. Acoels, as part of the phylum Xenacoelomorpha, are considered the sister group of the remaining bilaterians. Therefore, knowing the spatial organization of this cell types can help us to shed some light in the evolution of ogans’ architectures.

Teachers: areas of knowledge