Contribution of duplication and mobile elements to genome divergence. (a) A simple model to show the contribution of duplication and mobile elements to gene divergence. (b) Genome-wide identification of duplication and mobile elements. Both tandem and segmental duplication related genes have been identified in genome-wide level. For mobile elements, both LTR retrotransposons and CACTA DNA transposons have been selected for genome-wide identification since these two elements consist of more 95% of mobile elements. (c) to (f) Ka/Ks analysis of duplicated pairs from segmental and tandem duplication, LTR-retrotransposition, CACTA transposition, respectively. Red and blue lines show the Ka/Ks values from within and between BT×623 and Keller, respectively.