Phylogeography of Nothofagus dombeyi reflects past geological and climatic changes in southern South America

MATHIASEN P; FASANELLA M; DIAZ DG; JURI G,; HASBUN R; AC PREMOLI

Congreso; II Virtual Meeting of Systematics, Biogeography, and Evolution SBE Meeting: The Research of Biodiversity and the Diversity of Researchers; 2021

The southern tip of South America has a long and complex geological history, whichbegun with the breakup of Gondwana and was followed by global sea level rises,tectonic processes such as mountain building and volcanism, glaciations, and the as-sociated climatic changes. The ancient flora of South America evolved under thesechanging environments. As a result, lineage diversification of long-lived woody taxa,such as Nothofagus, will reflect the effects of the Paleogene paleogeography of Patag-onia and more recent climatic oscillations of the Neogene. The objective was toevaluate the phylogeographic patterns of Nothofagus dombeyi combining geologicalevidence from marine sedimentary basins, Andean orogeny, and climatology withphylogenetic and statistical analyses. A total of 203 individuals along the entirerange of distribution of the species were sampled and analyzed by sequencing threenon-coding regions of the chloroplast DNA. We found 24 chloroplast DNA haplo-types across the range. The phylogenetic tree and the haplotype network yieldedthree strongly differentiated lineages that were latitudinally structured (AMOVAPhiST1-2=0.692, PhiST1-3=0.928, PhiST2-3=0.904). Two phylogeographic breakswere observed at 39◦S and 42◦S. The groups identified by BAPS and the PCA anal-ysis were in agreement with the three lineages. Lineage divergence was concordant with ancient geological events that took place during Eocene to Miocene epochs,while haplotype diversification within lineages was driven by more recent climaticchanges during the Pliocene. Middle-range Lineage 2 was the most polymorphic(67.11%), holding 15 of the 24 haplotypes, showing that marine transgressions (lateMiddle Miocene, Late Miocene, and Early Pliocene) could favor the great geneticdiversity. These ages have been assigned recently to Chilean formations near thePacific coast and across the Chilean Central Depression.