Abstract

Natural selection shapes genome-wide patterns of diversity within species and divergence between species. However, quantifying the efficacy of selection and elucidating the relative importance of different types of selection in shaping genomic variation remain challenging. We sequenced whole genomes of 101 individuals of three closely related oak species to track the divergence history, and to dissect the impacts of selective sweeps and background selection on patterns of genomic variation. We estimated that the three species diverged around the late Neogene and experienced a bottleneck during the Pleistocene. We detected genomic regions with elevated relative differentiation ('F-ST-islands'). Population genetic inferences from the site frequency spectrum and ancestral recombination graph indicated that F-ST-islands were formed by selective sweeps. We also found extensive positive selection; the fixation of adaptive mutations and reduction neutral diversity around substitutions generated a signature of selective sweeps. Prevalent negative selection and background selection have reduced genetic diversity in both genic and intergenic regions, and contributed substantially to the baseline variation in genetic diversity. Our results demonstrate the importance of linked selection in shaping genomic variation, and illustrate how the extent and strength of different selection models vary across the genome.

Keywords

ancestral recombination graph; background selection; genomic variation; linked selection; Quercus; recombination rate; selective sweeps

Published in

New Phytologist
2021, Volume: 233, number: 1, pages: 555-568
Publisher: WILEY

SLU Authors

• Ingvarsson, Pär

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany


Publication identifier

DOI: https://doi.org/10.1111/nph.17793

Permanent link to this page (URI)

https://res.slu.se/id/publ/114307