title: The mitochondrial genome sequences of the round goby and the sand goby reveal patterns of recent evolution in gobiid fish.
abstract: Vertebrate mitochondrial genomes are optimized for fast replication and low cost of RNA expression. Accordingly, they are devoid of introns, are transcribed as polycistrons and contain very little intergenic sequences. Usually, vertebrate mitochondrial genomes measure between 16.5 and 17 kilobases (kb).
  
  
  
  During genome sequencing projects for two novel vertebrate models, the invasive round goby and the sand goby, we found that the sand goby genome is exceptionally small (16.4 kb), while the mitochondrial genome of the round goby is much larger than expected for a vertebrate. It is 19 kb in size and is thus one of the largest fish and even vertebrate mitochondrial genomes known to date. The expansion is attributable to a sequence insertion downstream of the putative transcriptional start site. This insertion carries traces of repeats from the control region, but is mostly novel. To get more information about this phenomenon, we gathered all available mitochondrial genomes of Gobiidae and of nine gobioid species, performed phylogenetic analyses, analysed gene arrangements, and compared gobiid mitochondrial genome sizes, ecological information and other species characteristics with respect to the mitochondrial phylogeny. This allowed us amongst others to identify a unique arrangement of tRNAs among Ponto-Caspian gobies.
  
  
  
  Our results indicate that the round goby mitochondrial genome may contain novel features. Since mitochondrial genome organisation is tightly linked to energy metabolism, these features may be linked to its invasion success. Also, the unique tRNA arrangement among Ponto-Caspian gobies may be helpful in studying the evolution of this highly adaptive and invasive species group. Finally, we find that the phylogeny of gobiids can be further refined by the use of longer stretches of linked DNA sequence.
authors.affiliation: Program Man-Society-Environment, Department of Environmental Sciences, University of Basel, Vesalgasse 1, Basel, 4051, Switzerland. irene.adrian-kalchhauser@unibas.ch.
authors.forename: Irene
authors.identifier: 0000-0002-7563-2577
authors.initials: I
authors.lastname: Adrian-Kalchhauser
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18A, 41390, Göteborg, Sweden.|The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, P.O. Box 460, 40530, Gothenburg, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Svensson
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden.
authors.forename: Verena E
authors.initials: VE
authors.lastname: Kutschera
authors.affiliation: The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, P.O. Box 460, 40530, Gothenburg, Sweden.|Department of Marine Sciences, NBIS Bioinformatics Infrastructure for Life Sciences, University of Gothenburg, Medicinaregatan 9C, 41390, Gothenburg, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Alm Rosenblad
authors.affiliation: Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Pippel
authors.affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307, Dresden, Germany.
authors.forename: Sylke
authors.initials: S
authors.lastname: Winkler
authors.affiliation: Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Schloissnig
authors.affiliation: The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, P.O. Box 460, 40530, Gothenburg, Sweden.|Department of Marine Sciences, University of Gothenburg, Medicinaregatan 9C, 41390, Gothenburg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Blomberg
authors.affiliation: Program Man-Society-Environment, Department of Environmental Sciences, University of Basel, Vesalgasse 1, Basel, 4051, Switzerland.|Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, Canada.
authors.forename: Patricia
authors.initials: P
authors.lastname: Burkhardt-Holm
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D015321:Gene Rearrangement; D054629:Genome, Mitochondrial / Q000235:genetics*; D010473:Perciformes / Q000235:genetics*; D010802:Phylogeny; D000073336:Whole Genome Sequencing
keywords: Genome organisation; Genome size; Gobiidae; Mitogenome; Neogobius melanostomus; Phylogeny; Pomatoschistus minutus; Ponticola kessleri; Salinity