Sang-Oun Jung

The complete mitochondrial genome of the rayfish Raja porosa (Chondrichthyes, Rajidae).

We isolated mitochondrial DNA from the rayfish Raja porosa by long-polymerase chain reaction (Long-PCR) with conserved primers, and sequenced it by primer walking method using flanking sequences as sequencing primers. R. porosa mitochondrial DNA consists of 16,972 bp and its structural organization is conserved in comparison with other fishes and mammals. Based on the mitochondrial cytochrome b (cyt b) sequence, the phylogenetic position of R. porosa among cartilaginous fishes was inferred using different phylogenetic methods (ML-based quartet puzzling, Neighbor-joining (NJ) and Bayesian approaches). In this paper, we report the characteristics of the R. porosa mitochondrial genome including structural organization, base composition of rRNAs, tRNAs and protein-encoding genes and characteristics of mitochondrial tRNAs. These findings are applicable to comparative mitogenomics of R. porosa with other related taxa.

The complete mitochondrial genome of the Korean soft-shelled turtle Pelodiscus sinensis (Testudines, Trionychidae)

We isolated Korean soft-shelled turtle, Pelodiscus sinensis, mitochondrial DNA by long-polymerase chain reaction (long-PCR) with conserved primers and sequenced this mitochondrial genome (mitogenome) with primer walking using flanking sequences. The P. sinensis mitochondrial DNA has 17,042 bp and its structural organization is conserved compared to those of other reptiles and mammals. To unveil the phylogenetic relationship of the turtles, we used the NJ, MP, and ML analysis methods after inferring those sequences from the mitochondrial 16S rRNA gene. We also compared two P. sinensis variants from Korea and China using the mitochondrial genome. In this study, we report the basic characteristics of the P. sinensis mitochondrial genome, including structural organization and base composition of the rRNAs, tRNAs and protein-coding genes, as well as characteristics of tRNAs. These features are applicable for the study of phylogenetic relationships in turtles.

Mitochondrial genome of Thais clavigera (Mollusca: Gastropoda): affirmation of the conserved, ancestral gene pattern within the mollusks.

Class Gastropoda includes a large number of described species, many with extensively rearranged mitochondrial genomes. We sequenced the mitogenome of the rock shell, Thais clavigera (Gastropoda: Muricidae), an intertidal snail, using long PCR with primers designed on the basis of expressed sequence tags. The mitogenome of T. clavigera consists of 2 rRNAs, 22 tRNAs, and 13 protein-coding genes, but no control region. Structural comparisons revealed that the order Sorbeoconcha, including T. clavigera, have nearly identical mitochondrial gene patterns. However, they have an inversion between a tRNA(Phe)-tRNA(Glu) cluster that comprises 21 genes, but most of the remaining structure is similar to the putative mollusk ground pattern. These findings will provide a better insight into mitochondrial gene rearrangement over the course of gastropod evolution.

cDNA cloning and expression of ferritin heavy chain 1, ferritin heavy chain 2 and hemoglobin genes from the fire-bellied frog Bombina orientalis

We cloned two Bombina orientalis ferritin heavy chains (ferritin heavy chains 1 and 2) and one hemoglobin β-chain gene from a B. orientalis oviduct cDNA library, and the length of transcripts was 882, 858 and 611 bp encoding 177, 177 and 148 aa, respectively. B. orientalis ferritin heavy chain genes showed high similarity to those of amphibia (88–93%), mammals (70–71%), and fishes (70–72%), and the hemoglobin β-chain gene showed moderate similarity to amphibian (65–68%) and mammalian (54–57%) hemoglobin β-chain genes, respectively. Based on phylogenetic analysis, the genes were clustered to the same clade in amphibia. The two B. orientalis ferritin heavy chain genes showed different tissue-specific gene expression patterns. Thus, ferritin heavy chain 1 gene was highly expressed in intestine and oviduct but ferritin heavy chain 2 gene was ubiquitously expressed in most of the examined tissues. The hemoglobin β-chain gene was more highly expressed in liver than in oviduct. These findings indicate that the genes may play different roles in different tissues. In this paper, we discuss the basic characteristics of B. orientalis ferritin heavy chain genes and hemoglobin β-chain gene.