Fig. 1

Gene expression diversity in the whole-genome gene set (WGGS) and candidate selected gene set (CSGS) for the seven pairs. a Expression diversity of the WGGS. b Expression diversity of the CSGS. The samples of soybean could be clearly classified as wild, landraces and improved cultivars. The other six pairs were grouped into wild and domestic species. The markers above the solid black lines are the P-value from a Student’s t-test of whether the expression diversity values in the domestic species are significantly lower than those in the wild species and the P-value less than 0.05, 0.01 and 0.001 are marked with *, ** and ***, separately. The expression diversity changes of the two subgenomes of cotton can be found in the supplementary information (Additional file 1: Figure S1)