Evolution of posterior elongation process in chordates

Projet en recherche de financement

Project affiliated to:
Project leader Observatoire Océanologique de Banyuls
Budget 869 K€
Year of labeling 2009

The project aims to understand the evolution of a key developmental process, the posterior elongation among chordates.

Posterior elongation is the process by which the embryo grows in the anterior-posterior axis from the caudal region.

It is characterized by a great diversity in terms of anatomy of the tail bud, which is the elongating structure, and in terms of cell fate in different chordates.

However, some gene expression data in different chordate lineages suggest a common evolutionary origin of the molecular mechanisms controlling the process of elongation.

Thus, FGF, Wnt and retinoic acid signalling pathways may have been involved in the control of this process in all chordate ancestors. The main goal of this project is to determine if there is indeed a common molecular network controlling the tail bud elongation processes in all chordates.

In other words, have the morphological processes of elongation diverged between different lines of chordates whilst keeping a common molecular and thus inherited control?

Or, on the contrary, did different elongation processes appear several times during evolution by convergence, creating the current morphological diversity in the caudal bud in chordates?

The experimental approach is part of an Evo-Devo study. It is therefore a comparative approach.

It is a study of the morphological and functional mechanisms involved in the process of posterior elongation in amphioxus.

Indeed, through its phylogenetic position at the origin of chordates, as well as through its character which owes little to its morphology and its genome, this model is the only existing metazoan which can be used for comparative studies capable of answering key questions about chordate evolution.

The comparison of these results with what is known about vertebrates will allow for hypotheses on the evolution of the posterior process of elongation in this line to be made.