Fig. 6

Position class (Pcl) information of cox1 genes in the 19 species. Introns in cox1 genes of 19 published mitogenomes were classified into different position classes (Pcls) using the cox1 gene of Ganoderma calidophilum as the reference. Each Pcl was constituted by introns inserted at the same position of corresponding cox1 gene and named according to its insertion site in the aligned corresponding reference sequence (nt). The Pcls present in more than 1/5 of species were considered as common Pcls, while introns detected in less than 1/5 of species were considered to be rare introns. Phylogenetic positions of the 19 species were established using the Bayesian inference (BI) method and Maximum Likelihood (ML) method based on combined mitochondrial data sets. Species information is shown in Additional file 1: Table S7