Mitochondrial genome evolution in Ophiuroidea, Echinoidea, and Holothuroidea: insights in phylogenetic relationships of Echinodermata.
The genome architecture and amino acid sequences of six new complete mitochondrial genomes were determined from representatives of Hemichordata (1), Ophiuroidea (3), Echinoidea (1) and Holothuroidea (1) and were analysed together with previously known sequences. Phylogenetic analyses recovered three lineages within echinoderms, Crinoidea, Ophiuroidea and a group comprising Holothuroidea, Echinoidea, and Asteroidea. In contrast to previous analyses of mitochondrial genomes the increased data set recovered the classical echinoderm phylogeny of Eleutherozoa and Echinozoa in Maximum Likelihood and Bayesian analyses using hemichordate out-group representatives. However, an inconsistent ramification appeared with vertebrate out-groups and in Maximum Parsimony and Neighbour Joining reconstructions. The basal (consensus) gene orders of all three lineages could be derived from a hypothetical ancestral crinoid gene order by one single rearrangement in each lineage. The genome architecture was highly conserved in Echinoidea, whereas the highest gene order differences and large amounts of unassigned sequences (UAS) were detected in Ophiuroidea, supporting a higher evolutionary rate than in any other echinoderm lineage. The variability in gene order and UAS regions in ophiuroid genomes suggest dominating rearrangement mechanisms by duplication events.
Institute of Biology II: Zoologie, Molekulare Evolution und Systematik der Tiere, University of Leipzig, Leipzig, Germany.
Marleen
M
Perseke
Detlef
D
Bernhard
Guido
G
Fritzsch
Franz
F
Brümmer
Peter F
PF
Stadler
Martin
M
Schlegel
D000818:Animals; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics; D004447:Echinodermata / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D023061:Gene Order; D015321:Gene Rearrangement; D054629:Genome, Mitochondrial; D016013:Likelihood Functions; D010802:Phylogeny; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial