Phylogeology - genes speak for history: the case of Nothofagus

MATHIASEN P.; ACOSTA M. C.; PREMOLI A. C.

Punta Arenas

Congreso; VIII Southern Connection Congress; 2016

Southern Connection

Thedistribution of genetic patterns within a landscape is the result of complexprocesses occurring at different timescales. Phylogeographic studies have madea significant contribution to the interpretation of genetic lineagedistribution in response to recent climate changes (such as glaciation eventsof the Neogene). However, the effects of ancient tectonic processes andclimatology driving lineage evolution have been largely overlooked.Phylogeology is an emerging field, as the study of the geographic distributionof ancient lineages to infer the effects of geological processes. These effectscan be tested in widespread lineages of cold-tolerant species that have enduredcooling. We hereby combine geological evidence from marine sedimentary basins,Andean orogeny, and climatology with molecular dating and statisticalphylogeography to infer how geological and climatic processes affected thedistribution of genetic lineages in cold-tolerant Nothofagusspecies. Samples ofthe entire range of all five species within the genus Nothofaguswere analyzedby sequencing three cDNA non-coding regions. We found 30 haplotypes that weregeographically structured. Fossil calibrated molecular dating revealed thatancestral lineages appeared by the Eocene/Oligocene, whereas most divergencestook place during the Miocene; and posterior population expansion occurred inthe Early Pleistocene (1.5?1 Ma). Lineage divergence from all wide-rangingNothofaguswas spatially and temporally concordant with episodic marine transgressionsand warmer times in Patagonia during Eocene/Miocene Epochs. Long-lasting stableraised areas preserved haplotype diversity throughout Patagonia, from wherecold-tolerant taxa expanded their ranges during preQuaternary times.