Symposium GT Evolution Expérimentale Occitanie : "interactions écologiques dans l'évolution expérimentale"

Le 13 Juin 2019
ISEM - Montpellier (salle Louis Thaler)

Une réunion du groupe « Évolution Expérimentale Occitanie » aura lieu le 13 juin 2019 à l’ISEM de Montpellier (salle Louis Thaler).

La journée est dédiée au thème des « Écologie Évolutive des interactions » (hôte-parasite, prédateur-proie, compétition, mutualisme…).

Nous proposons une formule journée entière, avec des présentations de nos deux invités (Sara Mitri & Lutz Becks ; titres et résumés ci-dessous) et des présentations courtes (10minutes+discussion).


Programme provisoire :

à partir de 9h :           café/thé & croissants

9h30 :                          Lutz Becks : The feedback between selection and demography shapes genomic diversity during coevolution

10h30-12h :                Présentations courtes & discussion

12-14h :                       Lunch (aux jardin de l’ISEM)

14h :                            Sara Mitri : Experimentally evolving a four-species bacterial community

15-16h30 :                  Présentations courtes & discussion

17h :                            Fin de la journée

le soir :                        Resto avec les invités


Présentations :

Nous avons de la place pour 10-12 présentations courtes. Si vous voulez faire un exposé, cliquez sur l’onglet  “Dépôts” dans votre “Espace connecté” sur le site web ( Vous pourrez ainsi déposer titre & résumé.

Deadline pour proposer une présentation : 31 mai.


Invited speakers:

LUTZ BECKS (Universität Konstanz)

The feedback between selection and demography shapes genomic diversity during coevolution

Organisms can often adapt surprisingly quickly to changes in their environment. For instance, the fast adaptation of resistance against pesticides or antibiotics, as well as the rapid coevolution of interacting species, suggest an abundant supply of adaptive genetic variation. There are however different evolutionary processes that affect the rate and trajectories of evolutionary change on the genotypic and ultimately on the phenotypic level. Typically, these evolutionary forces act simultaneously and their respective contribution to the overall evolutionary outcome changes over time and space. This becomes in particular important with the notion of rapid evolution when adaptive changes and changes in population size occur at the same time scale, so called eco-evolutionary dynamics. These entangled dynamics further complicate our interpretation of the roles of selection and demography, as the relative importance of the two might change rapidly and continuously. I will present results from our work where we combine experimental evolution studies in microbial systems with genomics analyses to disentangle the relative roles of selection and demography over time in different communities and under different environmental conditions.


SARA MITRI (Université de Lausanne)

Experimentally evolving a four-species bacterial community

Evolutionary dynamics are little understood within large microbial communities. Disentangling how microbial species co-evolve over time and alter their interactions with one another needs to first be carried out on simpler ecosystems. We have focused on a synthetic bacterial community consisting of just four species involved in bioremediation. Using a well-defined medium, the four species grow in a closed system, in which we can closely follow bacterial abundances, the interactions between the four species and their genetic changes, during a long- term evolutionary experiment. For comparison with the four-species community, our experiment included two mono-culture conditions and one community of three that were all passaged in parallel.  Before the beginning of this evolutionary experiment, we determined that the species have positive growth effects on one another. We then ask: what will happen to these positive interactions over time? And what are the key genetic changes that will occur as bacteria adapt to the environment and to the other species? Over approximately 500 generations, we find that species abundances fluctuate following patterns that differ depending on community composition. Out of five replicate communities containing all four species, three resulted in stable co-existence. Preliminary results from metagenomic sequencing of the populations also suggest that some mutations are consistent between replicates, but differ depending on which species where co-cultured. We are yet to assess how the interactions have changed and to complete our genomic analysis, but expect these results to be available by the time of the meeting.


Contacts :

Oliver Kaltz,

Stéphanie Bedhomme,


Inscription :

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Deadline pour confirmer votre participation : 7 juin