Le CEA-Genoscope vous invite à son prochain séminaire sur le thème :

"The universal markers and the conflicting signals"

Le séminaire est présenté par Morgan Gaia, Institut Pasteur

Invité par Olivier Jaillon

Lieu :

CEA-Genoscope
Bat G2
Rue Gaston Crémieux
Evry

Entrée libre

Résumé :

Most tree of life studies rely on the analyses of genes conserved between the three domains. In order to get a vertical evolutionary signal among potential horizontal transfers, these conserved genes are often concatenated together ; the resulting phylogenetic tree hence reflects the global signal carried by the majority of the genes, supposed to correspond to a species tree. However, universal markers concatenations do not systematically carry one global signal with minor noise, but contradicting signals supported by sets of genes. As a consequence, phylogenetic trees obtained from concatenated proteins can reflect the strongest signal within the markers, which is dependent on the markers used or potential biases. This raises several questions : which markers evolved along the species tree ? What does the remaining signal(s) reveal ? Does the repartition of universal markers in different sets correspond to differences in protein size, function, or other factors ? To get more insights on these points, we are performing extensive phylogenetic analyses on each universal marker, individually and in different concatenations. This approach also allows the study of complex co-evolutionary patterns between cells and viruses sharing markers, an aspect rarely considered in the topology of the tree of life and the different associated scenarios.