The expanded and contracted families focused on in this study were confirmed using Fisher’s exact test. For each gene family, we compared the gene count of the tested family in G. elata (copy number of the tested family as numerator, total number of genes of the whole genome as denominator) versus the frequency in D. officinale8,9, P. equestris7, A. comosus10, and Arabidopsis thaliana (phytozomev10). In addition, phylogenetic trees were constructed for each family to confirm gene gain or loss events. The extreme case of gene lost was that one gene was absent in the G. elata genome. To avoid false positive gene absence events caused by missing gene annotations, a TBLASTN search against the G. elata genome was carried out using protein sequences derived from other plant genomes.