Expression profiles of the 75 soybean expansin genes. The hierarchical cluster color code: the largest values are displayed as the reddest (hot), the smallest values are displayed as the bluest (cool), and the intermediate values are a lighter color of either blue or red. Raw data were normalized by the following equation: reads/kilobase/million. Pearson correlation clustering was used to group the developmentally regulated genes. Six genes were excluded from the analysis because they were not expressed in an organ or a period. The red outlined boxes represent the small phylogenetic clades that had a largely similar transcript abundance profile.