Figure 2.

Proposed mechanism of gene rearrangements in the seventeen Heptageniidae mitogenomes. Gene sizes are not drawn to scale. Genes encoded by the L-strand are underlined, whereas those without underline are encoded on the H-strand. Different colored boxes represent different genes. The remaining genes and gene orders that were identical to the ancestral insect are left out. Horizontal lines, asterisk symbols, and crossed-out symbols represent gene duplications, gene mutations, and gene deletions, respectively. (A) Rearrangement of I-M-Q-M; (B) rearrangement of I-M-Q-NCR.