To determine which genomic elements play a significant role in shaping mt gene order evolution, if any, we first obtained the number of mt protein-coding genes, introns, intronic ORFs, and repeats in all our sampled genomes.
The frequency of inversions and the absence of any other types of mt genome rearrangements suggest a unique mode of mt gene order evolution in Octocorallia, especially when compared to its presumed sister clade, Hexacorallia.
For this reason, bivalve mitochondrial genome may provide an excellent experimental system to review and test models of mt gene rearrangement evolution, which were mainly developed in groups with stable genomes, such as vertebrates or arthropods.
These genomes strongly support the TDRL model of mt gene rearrangements and concerted evolution between duplications.
If mtMutS is similarly capable of double-stranded break repair, its activity could promote the recombinational processes that underlie the evolution of mt gene order in Octocorallia.
In this study, we analyze the evolution of mt gene order arrangements within gastropods in order to gain insights on rates and mechanisms of genome rearrangement within the group.
Altogether our findings provide novel data on the evolution and diversification of MT gene duplicates, a valuable resource for understanding the vast set of biological processes in which these proteins are involved.
The afrobatrachian mt data supported the first tandem and second non-tandem duplication model for mt gene rearrangements and the recombination-based model for concerted evolution of duplicated mt regions.
In the current study, the complete mtDNA of 16 ardeid species was sequenced in order to explore the occurrence of derived, rather than ancestral avian, mt gene orders in ardeid mt genomes and to investigate the evolution of mt gene rearrangements in the family Ardeidae.
The mt gene order of Heleophryne regis is key for understanding the evolution of mt genome rearrangements in neobatrachians given that this species is basal in this clade (see reconstructed phylogeny in Figure 1).
