Disentangling local adaptation drivers in the Andean Nothofagus pumilio

ARANA, M. V.; PASTORINO, M.J,; OPGENOORTH, L.; SEKELY, J; MATTERA MG; HEER, K.; MARCHELLI, P; SOLIANI C

Conferencia; Genomics and Adaptation in Forest Ecosystems; 2021

Disentangling the effects of individual environmental factors is important fordetermining the driving factors of local adaptation. However, natural forests inhabitlandscapes with overlapping and interacting environmental gradients, which makesthis endeavor notoriously difficult in situ. The cold-adapted Nothofagus pumilioforests present an ideal study system because they stretch over a 2000-kilometerrange, from the high-altitude subtropics (35°S) to sea level at the southernmost tip ofTierra del Fuego (56°S). This species inhabits the southern Andes mountains, whichrun almost perfectly North to South and contain clear precipitation, day-length, andtemperature gradients, which are three of the most biologically importantenvironmental gradients. To assess in situ adaptation, we sampled 500 N. pumilioadults along these gradients using a paired-site sampling design. A pair containedtwo sites that were close enough to share an evolutionary history but far enoughapart in elevation to experience different temperature conditions. Using a set of~50,000 SNPs from candidate genes and the CHELSA dataset of global climateparameters, we performed an association genetic analysis to discover genes thatmay be under selection. We investigated population structure (e.g. ADMIXTURE),possible SNP outliers (pcadapt, outFLANK), and gene?environment associations(LFMM2). These results will fuel further downstream analyses of local adaptationincluding phenotype?environment associations and demographic history inference.