title: Gene rearrangements in gekkonid mitochondrial genomes with shuffling, loss, and reassignment of tRNA genes.
abstract: BACKGROUND
  Vertebrate mitochondrial genomes (mitogenomes) are 16-18 kbp double-stranded circular DNAs that encode a set of 37 genes. The arrangement of these genes and the major noncoding region is relatively conserved through evolution although gene rearrangements have been described for diverse lineages. The tandem duplication-random loss model has been invoked to explain the mechanisms of most mitochondrial gene rearrangements. Previously reported mitogenomic sequences for geckos rarely included gene rearrangements, which we explore in the present study.
  
  
  RESULTS
  We determined seven new mitogenomic sequences from Gekkonidae using a high-throughput sequencing method. The Tropiocolotes tripolitanus mitogenome involves a tandem duplication of the gene block: tRNAArg, NADH dehydrogenase subunit 4L, and NADH dehydrogenase subunit 4. One of the duplicate copies for each protein-coding gene may be pseudogenized. A duplicate copy of the tRNAArg gene appears to have been converted to a tRNAGln gene by a C to T base substitution at the second anticodon position, although this gene may not be fully functional in protein synthesis. The Stenodactylus petrii mitogenome includes several tandem duplications of tRNALeu genes, as well as a translocation of the tRNAAla gene and a putative origin of light-strand replication within a tRNA gene cluster. Finally, the Uroplatus fimbriatus and U. ebenaui mitogenomes feature the apparent loss of the tRNAGlu gene from its original position. Uroplatus fimbriatus appears to retain a translocated tRNAGlu gene adjacent to the 5' end of the major noncoding region.
  
  
  CONCLUSIONS
  The present study describes several new mitochondrial gene rearrangements from Gekkonidae. The loss and reassignment of tRNA genes is not very common in vertebrate mitogenomes and our findings raise new questions as to how missing tRNAs are supplied and if the reassigned tRNA gene is fully functional. These new examples of mitochondrial gene rearrangements in geckos should broaden our understanding of the evolution of mitochondrial gene arrangements.
authors.affiliation: Department of Information and Biological Sciences and Research Center for Biological Diversity, Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya 467-8501, Japan. kuma@nsc.nagoya-cu.ac.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kumazawa
authors.forename: Saaya
authors.initials: S
authors.lastname: Miura
authors.forename: Chiemi
authors.initials: C
authors.lastname: Yamada
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Hashiguchi
mesh_terms: D000818:Animals; D001483:Base Sequence; D003062:Codon; D015321:Gene Rearrangement; D054629:Genome, Mitochondrial; D059014:High-Throughput Nucleotide Sequencing; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000737:chemistry / Q000235:genetics; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012104:Reptiles / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D003062:Codon; C098483:NADH dehydrogenase subunit 4; D012343:RNA, Transfer; D009245:NADH Dehydrogenase