Genome-wide patterns of differentiation and spatially varying selection between postglacial recolonization lineages of Populus alba (Salicaceae), a widespread forest tree

Malden

Blackwell Science Ltd.

2015

S. 723-734

BandaufführungSonderdruck

191851

New Phytologist 2015 : ONLINE ONLY : International Journal of Plant Science, S. 723-734

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, 9134 high-differentiation (. 4 standard deviations) outlier SNPs were uncovered between populations, 848 of which were shared by . three 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 ehard selective sweeps f vs divergent selection of standing genetic variation in distinct postglacial recolonization lineages of P. alba.
Key words: adaptation, divergence ; continuum, divergent selection, population ; genomics, Populus, postglacial recolonization, selective sweep, whole-genome sequencing.
Schlüsselwörter: Anpassung, Divergenz; Kontinuum, divergente Selektion, Bevölkerung; Genomik, Populus, postglaziale Rekolonisierung, selektiver Sweep, Sequenzierung des gesamten Genoms.