title: Complete mitochondrial genomes of two Japanese precious corals, Paracorallium japonicum and Corallium konojoi (Cnidaria, Octocorallia, Coralliidae): notable differences in gene arrangement.
abstract: Precious coral are taxonomically a group of corals that belong to the family Coralliidae within the order Alcyonacea, subclass Octocorallia, and class Anthozoa, whose skeletal axes are used for jewelry. They are distributed in the Mediterranean Sea and in waters adjacent to Japan, Taiwan, Midway Island and the Hawaiian Islands. The genus Corallium of the family Coralliidae was recently divided into two genera, Corallium and Paracorallium, based on morphological observations, but insufficient molecular evidence to support this classification has been presented to date. We determined for the first time the complete mitochondrial genome sequence of two precious corals P. japonicum and C. konojoi, in order to clarify their systematic positions. The circular mitochondrial genomes of P. japonicum and C. konojoi are 18,913bp and 18,969bp in length, respectively, and encode 13 typical energy pathway protein coding genes (nad1-6, nad4L, cox1-3, cob, atp6 and atp8), two ribosomal RNA genes (rns and rnl), a transfer RNA (trnM) and a mismatch repair gene homologue msh1. The two genomes have an overall nucleotide sequence identity of 97.5%, which is comparable to that between Acanella eburnea and Keratoisidinae sp. belonging to Octocorallia. Surprisingly, however, their gene arrangements were not identical. Phylogenetic analyses using seven complete mitochondrial genome sequences belonging to species in the subclass Octocorallia indicated that within the subclass, at least three gene order rearrangement events occurred during evolution. Our results support the validity of the morphological classification that separated the family Coralliidae into two genera, Corallium and Paracorallium.
authors.affiliation: Laboratories of Biochemistry, Faculty of Science, Kochi University, Kochi 780-8520, Japan. k-uda@cc.kochi-u.ac.jp
authors.forename: Kouji
authors.initials: K
authors.lastname: Uda
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Komeda
authors.forename: Hiwa
authors.initials: H
authors.lastname: Koyama
authors.forename: Kumiko
authors.initials: K
authors.lastname: Koga
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Fujita
authors.forename: Nozomu
authors.initials: N
authors.lastname: Iwasaki
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000145:classification / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D023061:Gene Order; D015321:Gene Rearrangement; D054629:Genome, Mitochondrial; D055029:Inverted Repeat Sequences; D007564:Japan; D024101:Mitochondrial Proteins / Q000235:genetics; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D016415:Sequence Alignment; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D021901:DNA, Intergenic; D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D012335:RNA, Ribosomal; D012343:RNA, Transfer