PhD opportunities in Montpellier to work on pretty ascidian embryos!

Applications are open for 3-year PhD fellowships in the Montpellier Health Science doctoral program (To apply visit http://www.adum.fr/as/ed/cbs2/page.pl?page=concoursed-gb before May 3rd 2016).

Our group is proposing three possible independent PhD projects on the embryonic development of marine invertebrates closely related to vertebrates, the ascidians (Lemaire, 2011, Development 138, 2143–2152). Most ascidian species develop with almost identical embryonic morphologies in spite of very different genomes, a paradox we are trying to understand. The projects will contribute to a better understanding of the genetic program underlying ascidian development and of its robustness to genetic changes.

The first project aims at the reconstruction and analysis of the early ascidian endodermal Gene Regulatory Network, which is currently only very partially known. We will combine the knowledge of open chromatin regions flanked with specific histone marks, transcription factor (TF) DNA-binding specificity and TF expression to predict the location of cis-regulatory sequences for endodermal regulatory genes, which will be tested and dissected by electroporation into live embryos. This network will then be used to model the flow of genetic information across time, and its robustness to genetic variations.

The second project will test the hypothesis that ascidians can buffer divergent genome information because the architecture of their Gene Regulatory Networks (GRNs) makes them quite insensitive to variations in the level of regulatory gene expression. This hypothesis will first be tested by comparing  the level of inter-individual variability in regulatory gene expression in ascidian embryos (slow morphological evolution, fast molecular evolution) and vertebrate embryos (faster morphological evolution, but slower molecular evolution). We will then monitor the phenotypic response to progressive interference with gene function in both taxa.

Finally, the third project will focus on inter-cellular communication (inductions) in ascidian embryos, and their sensitivity to changes in embryonic geometry and gene expression. We will first quantify the main biochemical parameters of an embryonic induction (concentrations of ligands and receptors, rates of diffusion, rate constants,…) and their variability across individuals. These data will then be used to construct and constrain a quantitative model of an embryonic induction.

Our group is small and interdisciplinary. Its working language is English.

(1 votes)

Loading...