The data in the GFF file used at SoyBase for the Wm82.a2 genome assembly was parsed into the component parts of the genes. For each gene we used the longest splice variant and determined (i) the full length of the gene, i.e. the region transcribed; (ii) the length of the CDS, i.e. the translated mRNA from ATG to TAG with introns removed; (iii) the length of the 5’ UTR (un-translated region) in the translated mRNA, i.e. with any introns removed; (iv) the length of the 3’ UTR in the translated mRNA, i.e. with any introns removed; (v) the combined length of all introns, i.e. those sequences spliced out of the 5’ UTR and/or the translated region and/or the 3’ UTR. These values were summed for all gene models in the Wm82.a2 genome assembly. We used the sum of the 5’ UTR, CDS and 3’ UTR lengths as the total exon length in the genome. The proportions of exon (11.6%) and intron (10.5%) sequences (S2 Table) are used as the expected values of random Tgm9 insertion into the soybean genome.