Gene expansion and expression divergence within a species. (a) The effect of segmental (top panel) and tandem (bottom panel) duplication on gene expression divergence. (b) Commonly or variety-specific expression divergence in BT×623 and Keller. (c) An example showing a gene undergoing both tandem and segmental duplication to give birth to new genes and their expression divergence. (d) Detected genes involved in both segmental and tandem duplication and their expression divergence. (e) The expression divergence between segmental and tandem duplication (green column) or between BT×623 and Keller (blue column) under sucrose treatment. (f) and (g) The effect of LTR-retrotransposons and CACTA elements on gene expression divergence. In (f) and (g), pink color shows pairs with no expression divergence, black color shows sucrose-related divergence pair and blue color shows the remaining divergence pairs.