title: Unusual sequence features and gene rearrangements of primitive crabs revealed by three complete mitochondrial genomes of Dromiacea.
abstract: Three complete mitochondrial genomes of primitive crabs, Dynomene pilumnoides (belong to Dromioidea), Homola orientalis and Moloha majora (belong to Homoloidea) were determined, characterized and compared with other brachyuran crabs. Due to the presence of four intergenic noncoding sequences (IGNs), the complete length of 16,475bp in D. pilumnoides is relatively large among brachyuran mitogenomes. Its longest IGN is 652bp in size locating between trnL1 and trnQ, which is regarded as putative control region (CR) considering its high similarity with the same superfamily species, Conchoecetes artificiosus and Takedromia cristatipes. Compared with the gene order of putative ancestors of insects and crustaceans, D. pilumnoides mitogenome exhibits rearrangements with positional translocation of three genes (trnQ, CR and trnH). The mitogenomes of H. orientalis and M. majora are 16,084bp and 15,903bp in size, respectively. Their gene arrangements are consistent with those reported for most brachyuran species. The lengths of CR in these two Homoloidea crabs are 1242bp and 1037bp, respectively. The occurrence of tandem repeat sequences (TRS) in control region is shared by the three Homoloidea crabs (besides Homologenus malayens), but is not found in the other reported brachyuran crabs. Moreover, the repeat units in H. orientalis and H. malayens show the high level of sequence identity with stable secondary structure. The phylogenetic analyses indicate that Dromioidea and Homoloidea form the most basal assemblage within Brachyura, followed by Raninoidea.
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Guohui
authors: G
authors: Shi
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; National & Local Joint Engineering Laboratory of Ecological Mariculture, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China. Electronic address: zhxcui@qdio.ac.cn.
authors: Zhaoxia
authors: Z
authors: Cui
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors: Min
authors: M
authors: Hui
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors: Yuan
authors: Y
authors: Liu
authors: Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
authors: Tin-Yam
authors: TY
authors: Chan
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Chengwen
authors: C
authors: Song
mesh_terms: D000818:Animals; D001483:Base Sequence; D003386:Brachyura / Q000235:genetics*; D021901:DNA, Intergenic / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D023061:Gene Order; D015321:Gene Rearrangement; D054629:Genome, Mitochondrial; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D021901:DNA, Intergenic; D004272:DNA, Mitochondrial
keywords: Dynomene ilumnoides; Gene order; Homola orientalis; Mitochondrial genome; Moloha majora; Non-coding region