Influence of social systems and population dynamics on the evolutionary responses to environmental pressures: A case study in western lowland gorillas

Alice Baudouin (1) , Hélène Rousseau (2) , Dominique Vallet (1) , Eric Petit (3) , Julien Boutte (2) , Armel Salmon (2) , Magdalena Bermejo (4) , José Domingo Rodriguez-Teijeiro , Victor Bonet-Arboli , Roser Farres Corell , Leslie Knapp , Nelly Ménard (1) , P. Le Gouar (1)

1 OSUR - Station Biologique de Paimpont CNRS UMR 6653
2 ECOBIO - Ecosystèmes, biodiversité, évolution [Rennes]
3 ESE - Écologie et santé des écosystèmes
4 ECOFAC

The group of genes coding for the major histocompatibility complex (MHC) are among the most polymorphic ones because they are involved in pathogens' defense. A high MHC variability improves the defense of individuals against a large range of pathogens and contributes to population sustainability. Population demographic crash is expected to strongly negatively affect the diversity of MHC. However, in social species, the type of social system is additional factor acting on the redistribution of MHC genes. Indeed, MHC is supposed to play a role in mate choice, although behavioral mechanisms (through olfactory communication or recognition of kinship) remain to be specified. We studied changes in MHC variability in a western lowland gorilla (Gorilla gorilla gorilla) population that suffered from a demographic crash due to Ebola epidemics. In this species, groups include only one dominant male that monopolizes the reproduction of its females. During natal or secondary dispersal, females join a solitary male or a new harem where they reproduce. We aimed at understanding the influence of gorilla social system on the effects of Ebola disturbance on MHC variability. We collected data on population structure and group composition through a long term monitoring of this population before and after Ebola and we used noninvasive DNA (i.e. feces) genetic analyses in order to investigate the intra and inter-group MHC variability before and after Ebola, and mate choice. We developed MHC haplotyping in gorillas using NGS and DGGE sequencing and a linked microsatellite. Preliminary results suggest that formation of new groups by solitary males after Ebola, possibly related to female mate choice, explained the changes in MHC variability. Applying this approach to other primate species with different social systems and different environmental pressures will allow to determine general patterns of the relative role of social and environmental pressure on MHC variability.

Domaines: Biodiversité et Ecologie

Alice Baudouin, Hélène Rousseau, Dominique Vallet, Eric Petit, Julien Boutte, et al.. Influence of social systems and population dynamics on the evolutionary responses to environmental pressures: A case study in western lowland gorillas. 27th International Congress for Conservation Biology, Society for Conservation Biology Global (SCB). Washington, D.C., USA., Aug 2015, Montpellier, France. ⟨hal-01161606⟩