par Fernández Mató, Pol 
Président du jury Dahdouh-Guebas, Farid
Promoteur Hardy, Olivier J.;Heuertz, Myriam
Publication Non publié, 2021-07-08
Président du jury Dahdouh-Guebas, Farid
Promoteur Hardy, Olivier J.
;Heuertz, Myriam Publication Non publié, 2021-07-08
Mémoire
| Résumé : | Understanding how speciation takes place is fundamental for future conservation strategies. Incipient speciation can be studied by examining the drivers of intra-specific genetic divergence. Here we aimed at shedding light on neutral and potentially adaptive evolutionary processes within the long-lived tropical tree species Symphonia globulifera L.f. that has a long evolutionary history (> 30 Ma) in the Guineo-Congolian rainforest in Africa. To accomplish our objectives we used a ddRAD-Seq dataset (double-digest restriction site associated DNA sequencing, 205 individuals and 818 filtered unlinked SNPs) from an extensive geographic sampling to obtain the maximum possible geographic resolution. We found a higher number of strongly differentiated genetic clusters compared to previous studies (K=10; mean FST=0.506-0.555, 95% confidence interval). Environmental factors such as bioclimatic variables, bioregion and soil type explained 23.5% of the genetic structure inside the species (F=2.941, P=0.001). The genetic structure of the dataset can also be explained in part by the barrier that the climatic inversion has represented in the history of this species (FST=0.108, randtest P=0.01). Finally, our results support the existence of a potentially new species or ecotype related to swamp habitats that has also apparent morphological differences from the other populations (Heuertz, M. and Hardy, O. (pers.com)). |
