Figure 1

Organization of the H. magnipapillata mt chromosomes (mt1 and mt2). A: In comparison to the linear mt genome of H. oligactis (Hydrozoa) and Aurelia aurita (Scyphozoa), drawn to scale. Arrows indicate orientation of genes in Aurelia. Numbered black bars above H. magnipapillata mt chromosomes correspond to the PCR fragments amplified from Hydra sp. (Additional file 3). Arrows in grey indicate the proposed duplications of terminal sequences in the mt chromosome separation process. B: Organization at the 5' and 3' ends of mt1 and mt2 in H. magnipapillata. Arrows in the inverted terminal repeats (ITR) are drawn according to the orientation of the cox1 fragment. C: Alignment of the ends of the ITR from H. oligactis, H. vulgaris (mt1) and H. magnipapillata (mt1 and mt2). * = sequence displayed as reverse complement.