Kyung Kil Kim

Erratum to: Isolation and characterization of polymorphic microsatellite markers for genetic analysis of chub mackerel (Scomber japonicus)

Chub mackerel, Scomber japonicus, is a species of major importance to fisheries, particularly in eastern Asia. To aid in the sustainable management of this fisheries resource, we isolated eight novel microsatellite loci from the fish and examined their polymorphisms to estimate genetic variability. Genetic variability differed at each locus. The number of alleles ranged from 5 to 14, and observed and expected heterozygosity ranged from 0.43 to 1.00 and 0.50 to 0.86, respectively. One locus showed significant Hardy–Weinberg disequilibrium. No linkage disequilibrium was found. The high variability revealed in this study suggests that these microsatellite markers could prove to be a useful tool for further conservation genetics studies.

Genetic diversity of wild and farmed black sea bream populations in Jeju

Abstract Black sea bream, Acanthopagrus schlegelii, is a commercially important fish in Korea. As a preliminary investigation into the effect of hatchery rearing for stock enhancement, we examined genetic diversity between wild and farmed black sea bream populations from Jeju using six microsatellite markers. High levels of polymorphism were observed between the two populations. A total of 87 different alleles were found at the loci, with some alleles being unique. Allelic variability ranged from 8 to 22 in the wild population and from 7 to 17 in the farmed one. Average observed and expected heterozygosities were estimated at 0.87 and 0.88 in the wild sample. The corresponding estimates were 0.83 and 0.86 in the farmed sample. Although a considerable loss of rare alleles was observed in the farmed sample, no statistically significant reductions were found in heterozygosity or allelic diversity in the farmed sample, compared with the wild one. Significant genetic heterogeneity was found between the wild and farmed populations. These results suggest that more intensive breeding practices for stock enhancement may have resulted in a further decrease of genetic diversity. Thus, it is necessary to monitor genetic variation in bloodstock, progeny, and target populations and control inbreeding in a commercial breeding program for conservation. This information may be useful for fisheries management and the aquaculture industry.

N-terminal pI determines the solubility of a recombinant protein lacking an internal transmembrane-like domain in E. coli

We examined whether the isoelectric point (pI) of the Nterminal region of the recombinant protein 7xMefp1 acts as a universal index for expression of the protein in soluble form in E. coli. Expression analysis of 7xMefp1 fused to various N-terminal sequences with pI values ranging from 2.73 to 13.35 yielded three pI range-specific curves (acidic, neutral, and alkaline curves at pI 2.73–3.25, 4.61–9.58, and 9.90–13.35, respectively) for soluble expression (by facilitated diffusion) as a proportion of total protein. For neutral N-termini (pI 4.61–9.58), the total amount of rMefp1 expressed was minimally affected by ΔGRNA for unfolding the mRNA secondary structure. The highly hydrophilic nature of longer N-terminal sequences with strongly acidic and alkaline pI values reduced the translation of rMefp1-encoding transcripts, thereby reducing the amount of soluble rMefp1 produced. After characterizing both feedback and non-feedback regulation in the acidic, alkaline, and neutral pI ranges, we suggest that three different pI range-specific soluble expression curves exist for the recombinant protein, each defined by specific ranges of the leader sequence pI values.

Genetic Differences between Wild and Cultured Populations in Olive Flounder in Korea Based on Mitochondrial DNA Analysis

We sequenced a 522 bp fragment including the tRNA Thr , tRNA Pro gene and the first half of the control region from 29 wild and cultured olive flounder specimens from Korea. Out of 522 nucleotide sites, 49 (9.4%) were variable, 23 haplotypes being found. Most haplotypes are unique in the wild population and only four were shared by cultured specimins. The nucleotide diversity and differences between wild and cultured populations were 0.025±0.013 and 0.015±0.008, and 12.94±6.00 and 7.83±3.75, respectively. Haplotype diversity was 0.98±0.02 and 0.49±0.09 in the wild and cultured populations, respectively. These results show that marked reductions of genetic variability in the hatchery strains were observed in the number of mitochondrial DNA haplotypes and haplotype diversity when compared to the wild populations. Furthermore, we detected significant population differentiation between both populations. The mtDNA sequencing technique used to evaluate the genetic variability of hatchery strains compared to that of the wild population is potential for genetic monitoring of olive flounder hatchery stocks.

Eleven new microsatellite markers in jack mackerel (Trachurus japonicus) derived from an enriched genomic library

Jack mackerel (Trachurus japonicus, Carangidae) are a commercially important fisheries resource in Korea. To understand patterns of genetic variation for conservation and management efforts, we developed microsatellite DNA markers fromT. japonicus. We report the isolation and characterization of eleven microsatellite loci isolated using an enrichment method based on magnetic/biotin capture of microsatellite sequences from a size-selected genomic library. To characterize each locus, 50 individuals from a naturalT. japonicus population in southern Korea were genotyped. All loci except one, KTJ38, were polymorphic with an average of 14 alleles per locus (range 6–23). The mean observed and expected heterozygosities were 0.70 (range 0.46–0.92) and 0.81 (range 0.49–1.00), respectively. Significant deviation from Hardy-Weinberg equilibrium was observed at three loci, KTj3, KTJ20 and KTJ28. Such high variability indicates that these microsatellites are useful markers for high-resolution analysis for population gemetic studies.