DOI: 10.5061/dryad.0817m
title: Data from: Genomic and functional approaches reveal a case of adaptive introgression from Populus balsamifera (balsam poplar) in P. trichocarpa (black cottonwood)

description: Natural hybrid zones in forest trees provide systems to study the transfer
 of adaptive genetic variation by introgression. Previous landscape genomic
 studies in Populus trichocarpa, a keystone tree species, indicated genomic
 footprints of admixture with its sister species P. balsamifera and
 identified candidate genes for local adaptation. Here, we explored
 patterns of introgression and signals of local adaptation in P.
 trichocarpa and P. balsamifera, employing genome resequencing data from
 three chromosomes in pure species and admixed individuals from wild
 populations. Local ancestry analysis in admixed P. trichocarpa revealed a
 telomeric region in chromosome 15 with P. balsamifera ancestry, containing
 several candidate genes for local adaptation. Genomic analyses revealed
 signals of selection in certain genes in this region (e.g. PRR5, COMT1),
 and functional analyses based on gene expression variation and
 correlations with adaptive phenotypes suggest distinct functions of the
 introgressed alleles. In contrast, a block of genes in chromosome 12
 paralogous to the introgressed region showed no signs of introgression or
 signatures of selection. We hypothesize that the introgressed region in
 chromosome 15 has introduced modular, or cassette-like variation into P.
 trichocarpa. These linked adaptive mutations are associated with a block
 of genes in chromosome 15 that appear to have undergone neo- or
 sub-functionalization relative to paralogs in a duplicated region on
 chromosome 12 that show no signatures of adaptive variation. The
 association between P. balsamifera introgressed alleles with the
 expression of adaptive traits in P. trichocarpa supports the hypothesis
 that this is a case of adaptive introgression in an ecologically important
 foundation species.
description: Original SNP data ch6 12
 15_replaceSNPs in three
 chromosomes (6, 12, 15) for 50 reference individuals (25 pure Populus
 balsamifera and 25 pure P. trichocarpa) and 68 admixed
 individualsOriginal_data_set_ch6_12_15.zipalpha estimates in introgressed regionsData from Table 2. Alpha estimate for three introgressed P. balsamifera regions in P. trichocarpa, one in chromosome (Chr) 06 (region A) and two in chromosome 15 (B and C).alpha.zipTajima and Nucleotide Diversity estimatesData for Figure 2, Figure 4 Supporting Information (Tajimas' D) and Figure 7 Supporting Information (Nucleotide diversity).Tajima_NucleotideDiversity.zipRASPberryData for Figure 1, Figure 2 supportive information and Figure 3 supportive information.LD_HaploviewData for Figure 3 and Figure 6 supportive information.NJ analysisData from Figure 1 Supporting information and Figure 5 Supporting informationNJ.zipGene_sequencesData for Figure 4, Figure 8 supportive information and Figure 9 supportive information.971Kb_filtered_datasetThis dataset was filtered based on minimum allele frequency (MAF &gt;0.1) and missing data (GR 0.95), for 25 reference P. trichocarpa, 25 reference P. balsamifera and 68 admixed accessions. The initial dataset consisted of 971K SNPs from 3691 genes in all 19 chromosomes.