On the relationship between structure and function of gene circuits : Study of evolvability and multi-functionality

Abstract

Per tal d'estudiar la relació complexa entre l'estructura d'un circuit genètic i la seva funció, ens centrem en estudiar dues proprietas: la seva capacitat evolutiva i la seva multi-functionalitat. Primer, fins a quin punt el mecanisme dinàmic portant a terme una funció fenotípica té un impacte en la capacitat d'evolucionar a nous fenotips? Hem descobert que circuits que utilitzen mecanismes alternatius difereixen en la probabilitat d'assolir noves funcions quan son sotmesos a mutacions. Segon, com pot un circuit mínim assolir dos patrons cel.lulars diferents? Hem descobert motius bi-funcionals capaços d'assolir inhibició lateral o bé inducció lateral depenent del teixit on es trobin. Hem estudiat el diseny d'aquest tipus de circuit i descobert que es poden dividir en dos tipus principals -hybrids o emergents--que corresponen a la seva capacitat en ser descompostos en differents sub-circuits, és a dir en la seva modularitat.

In order to study the complex relationship between the structure and function of gene circuits, we focus in the following two properties of circuits : their evolvability and multi-functionality. First, to what extent does the dynamical mechanism producing a specific biological phenotype bias the ability to evolve into new phenotypes? We find that circuits that use alternative mechanisms differ in the likelihood of reaching novel phenotypes through mutation. Second, how can a minimal circuit perform two distinct patterning functions? We discover bi-functional motifs able to perform lateral inhibition or lateral induction depending on the environment they are embedded in. We explore the design properties of multi-functional motifs and discover they can use two distinct types of design -hybrid or emergent- depending on their ability to be decomposed into distinct sub-circuits, i.e. their modularity.