Fig. 1

The comparison of various mitochondrial gene orders between ND5 and 12S rRNA: a typical vertebrate gene order (a), a typical avian gene order (b), an ancestral duplicated gene order assuming the tandem duplication of segment from cytb to CR (c), the most fully duplicated avian gene order, which was found in representatives of Bucerotiformes, Gruiformes, Procellariiformes, Psittaciformes and Suliformes (d), rearrangements that evolved by degeneration and/or loss of some duplicated elements in Palaeognathae and some Passeriformes: Notiomystis cincta and Turdus philomelos (e). ND5 – gene for NADH dehydrogenase subunit 5; cytb – gene for cytochrome b; T – gene for tRNA-Thr; P – gene for tRNA-Pro; ND6 – gene for NADH dehydrogenase subunit 6; E – gene for tRNA-Glu; CR – control region; F – gene for tRNA-Phe; 12S – gene for 12S rRNA. Pseudogenes are marked by ψ and colored correspondingly to their functional gene copy. Gene orders reannotated in this study are marked with an asterisk