Fig. 2.

A: Gene order resulting from a tandem duplication of the tThr to CR segment of the mitochondrial genome, and thought to be ancestral to the gene orders shown below. B–E: Gene orders surrounding the control region (CR) for five parrot species with duplicate control regions, each representing an independent origin of the duplicate control region state. Transfer RNAs are indicated by their single-letter abbreviations, E (Glutamyl), T (Threonine), P (Proline) and F (Phenylalanine). Pseudogenes are indicated with a “p” preceding the gene’s abbreviation. The gene order shown in A is that resulting from the tandem duplication illustrated in Figure 1, and which is the hypothesized precursor to the gene orders shown in B–E. Shading indicates hypothesized homology between highlighted regions.