Small introgressions between VNI, VNII, VNBI, and VNBII are dispersed throughout the genome and phylogeny. Introgressions were detected by running STRUCTURE (k = 4) on 500-kb blocks, excluding the mating type locus, and the group ancestry of each 5 kb within each block was identified. Recipient genomes are shown on the y-axis, and genomic position is shown on the x-axis. White indicates non-introgressed regions, and colored blocks indicate introgressed regions. The color key shows the color that corresponds to each donor group.