Complete mitochondrial genome of the catophragmid barnacle Catomerus polymerus (Cirripedia, Thoracica, Balanomorpha, Catophragmidae)

The family Catophragmidae is one of the lower balanomorphs from traditional and recent multiple mitochondrial and nuclear markers molecular analysis. Here, we characterized the first mitogenome of the catophragmid barnacle Catomerus polymerus, which was 15,446 bp in length with a 68.3% AT content. The mitogenome had the typical pancrustacean gene arrangement, which was identical to the mitogenome configurations of the chthamalid Octomeris sp. and pachylasmatoid Eochionelasmus ohtai. On the mitogenomic tree, the catophragmid Catomerus polymerus formed an independent branch that was basal to the members of the superfamilies Tetraclitoidea and Balanoidea, which was inconsistent with previous findings

Complete mitochondrial genome of the hydrothermal vent provannid snail Alviniconcha boucheti (Gastropoda: Abyssochrysoidea) from the North Fiji Basin

The family Provannidae is endemic to chemosynthetic environments in the deep-sea. Here, we report the complete mitogenome of a provannid vent snail Alviniconcha boucheti from the North Fiji Basin for the first time. The length of mitogenome was 15,981 bp, with 67.7% AT content. The mitogenome content and its protein-coding gene organization resembled those of other provannid snails. According to the phylogenetic tree, A. boucheti was most closely related to Ifremeria nautilei. Along with this result, further mitogenomic analysis of undetermined taxa within gastropods would improve our understanding in their taxonomic relationship and biogeography

Complete mitochondrial genome of the hydrothermal vent shrimp Rimicaris variabilis (Decapoda: Caridea: Alvinocarididae) from the North Fiji basin

The family Alvinocarididae is the monophyletic taxon which lives restrictively at chemosynthesis-based environments in the deep-sea. Here, for the first time, we report the complete mitogenome of the alvinocaridid vent shrimp Rimicaris variabilis from the North Fiji Basin. The mitogenome was 15,909 bp in length, with 65.6% AT content. Its protein-coding gene organization was typical of other alvinocaridid shrimps. Based on the phylogenetic tree, R. variabilis was most closely related to Shinkaicaris leurokolos, rather than with other Rimicaris species. To resolve this incongruence between traditional morphological classification and molecular analyses, further mitogenomic analysis of undetermined alvinocaridid taxa is necessary

Population genetic differentiation of the hydrothermal vent crab Austinograea alayseae (Crustacea: Bythograeidae) in the Southwest Pacific Ocean.

To understand the origin, migration, and distribution of organisms across disjunct deep-sea vent habitats, previous studies have documented the population genetic structures of widely distributed fauna, such as gastropods, bivalves, barnacles, and squat lobsters. However, a limited number of investigations has been conducted in the Southwest Pacific Ocean, and many questions remain. In this study, we determined the population structure of the bythograeid crab Austinograea alayseae from three adjacent vent systems (Manus Basin, North Fiji Basin, and Tonga Arc) in the Southwest Pacific Ocean using the sequences of two mitochondrial genes (COI and 16S rDNA) and one nuclear gene (28S rDNA). Populations were divided into a Manus clade and a North Fiji-Tonga clade, with sequence divergence values in the middle of the barcoding gap for bythograeids. We inferred that hydrographic and/or physical barriers act on the gene flow of A. alayseae between the Manus and North Fiji basins. Austinograea alayseae individuals interact freely between the North Fiji Basin and the Lau Basin (Tonga Arc). Although further studies of genetic differentiation over a geological time scale, life-history attributes, and genome-based population genetics are needed to improve our understanding of the evolutionary history of A. alayseae, our results contribute to elucidating the phylogeny, evolution, and biogeography of bythograeids

A gene clustering method with masking cross-matching fragments using modified suffix tree clustering method

Multiple sequence alignment is a method for comparing two or more DNA or protein sequences. Most multiple sequence alignment methods rely on pairwise alignment and Smith-Waterman algorithm [Needleman and Wunsch, 1970; Smith and Waterman, 198 1] to generate an alignment hierarchy. Therefore, as the number of sequences increases, the runtime increases exponentially. To resolve this problem, this paper presents a multiple sequence alignment method using a parallel processing suffix tree algorithm to search for common subsequences at one time without pairwise alignment. The cross-matched subsequences among the searched common subsequences may be generated and those cause inexact-matching. So the procedure of masking cross-matching pairs was suggested in this study. The proposed method, improved STC (Suffix Tree Clustering), is summarized as follows: (1) construction of suffix tree; (2) search and overlap of common subsequences; (3) grouping of subsequence pairs; (4) masking of cross-matching pairs; and (5) clustering of gene sequences. The new method was successfully evaluated with 23 genes in Mus musculus and 22 genes in three species, clustering nine and eight clusters, respectively

CLUSTOM: a novel method for clustering 16S rRNA next generation sequences by overlap minimization.

The recent nucleic acid sequencing revolution driven by shotgun and high-throughput technologies has led to a rapid increase in the number of sequences for microbial communities. The availability of 16S ribosomal RNA (rRNA) gene sequences from a multitude of natural environments now offers a unique opportunity to study microbial diversity and community structure. The large volume of sequencing data however makes it time consuming to assign individual sequences to phylotypes by searching them against public databases. Since ribosomal sequences have diverged across prokaryotic species, they can be grouped into clusters that represent operational taxonomic units. However, available clustering programs suffer from overlap of sequence spaces in adjacent clusters. In natural environments, gene sequences are homogenous within species but divergent between species. This evolutionary constraint results in an uneven distribution of genetic distances of genes in sequence space. To cluster 16S rRNA sequences more accurately, it is therefore essential to select core sequences that are located at the centers of the distributions represented by the genetic distance of sequences in taxonomic units. Based on this idea, we here describe a novel sequence clustering algorithm named CLUSTOM that minimizes the overlaps between adjacent clusters. The performance of this algorithm was evaluated in a comparative exercise with existing programs, using the reference sequences of the SILVA database as well as published pyrosequencing datasets. The test revealed that our algorithm achieves higher accuracy than ESPRIT-Tree and mothur, few of the best clustering algorithms. Results indicate that the concept of an uneven distribution of sequence distances can effectively and successfully cluster 16S rRNA gene sequences. The algorithm of CLUSTOM has been implemented both as a web and as a standalone command line application, which are available at http://clustom.kribb.re.kr