PRJNA274604
Populus alba pooled whole genome resequencing - Raw sequence reads
Studying the divergence continuum in plants is relevant to fundamental and applied biology because of the potential to reveal functionally important genetic variation. In this context, whole genome sequencing (WGS) provides the necessary rigour for uncovering footprints of selection. We resequenced populations of two divergent phylogeographic lineages of Populus alba (N=48), thoroughly characterized by microsatellites (N=317), and scanned their genomes for regions of unusually high allelic differentiation and reduced diversity using >1.7 million Single Nucleotide Polymorphisms (SNPs) from WGS. Results were confirmed by Sanger sequencing. On average 9,134 high-differentiation (=4 standard deviations) outlier SNPs were uncovered between populations, 848 of which were shared by =3 replicate comparisons. Annotation revealed that 545 of these were located in 437 predicted genes. Twelve percent of differentiation outlier genome regions exhibited significantly reduced genetic diversity. Gene ontology (GO) searches were successful for 327 high-differentiation genes, and these were enriched for 63 GO terms.Our results provide a snapshot of the roles of ‘hard selective sweeps’ versus divergent selection of standing genetic variation in distinct postglacial re-colonization lineages of P. alba. Thus, this study adds to our understanding of the mechanisms responsible for the origin of functionally relevant variation in temperate trees.