Comparison of the mitochondrial gene arrangements in copepods and the putative arthropod ground pattern. All tRNA genes and control regions were excluded for clarity. Gene segments are abbreviated as described in the main text, but are not drawn to scale. All elements were transcribed from left to right, with the exception of those depicted by shaded boxes. The horizontal lines illustrate gene blocks that are present in the Arthropod ground pattern. Large scale gene arrangements are apparent in copepods with all genes reshuffled.