Economic Impact of Donating a Kidney on Living Donors: A Korean Cohort Study.

RATIONALE & OBJECTIVE: Although existing studies have reported adverse health outcomes after kidney donation, its socioeconomic impact on living donors requires further study. STUDY DESIGN: A retrospective observational cohort study including a matched comparison group. SETTING & PARTICIPANTS: 1,285 living kidney donors from 7 tertiary hospitals between 2003 and 2016, and a matched comparison group consisting of the same number of health screening examinees with similar baseline clinical characteristics and socioeconomic status. All participants were receiving Korean national health insurance. EXPOSURE: Kidney donation as reflected in the Korean National Health Insurance System (NHIS) database. OUTCOME: Changes in household economic status estimated by Korean national health insurance fees and changes in employment status reflected in the NHIS database. ANALYTICAL APPROACH: The outcomes of the donor group and matched control group were compared annually using multivariable logistic regression analyses adjusted for clinical and demographic characteristics. RESULTS: The median ages of the donors and matched controls were 45 and 46 years, respectively; 44.6% of both groups were male. Compared to the comparison group, living donors were at higher risk of being unemployed or losing employment during the first 2 years after donation (eg, first-year loss of employment: odds ratio (OR), 2.27 [95% CI, 1.55-3.33]); however, this association did not persist. Donors also had a significantly lower odds of improvement in economic status (OR, 0.57 [95% CI, 0.47-0.71]) and a higher odds of deterioration in financial status (OR, 1.54 [95% CI, 1.23-1.93]) in the first year after transplantation and subsequently. LIMITATIONS: Unmeasured differences between donors and matched controls creating residual selection bias and confounding. CONCLUSIONS: Living kidney donors may suffer loss of employment and poor economic status after their voluntary donation. The socioeconomic impact on these donors should be considered in conjunction with the potential long-term adverse health outcomes after donation.

Association between early post-transplant hypertension or related antihypertensive use and prognosis of kidney transplant recipients: a nationwide observational study.

BACKGROUND: Additional research is warranted for the clinical significance of post-transplant hypertension and related antihypertensive medication use in kidney transplant (KT) recipients. METHODS: This observational study included nationwide KT recipients who maintained a functioning graft for at least 1 year after KT in South Korea, observed between 2008 and 2017. The use of antihypertensive medications lasting between 6 months and 1 year was the main exposure, and those who had inconsistent/transient use of antihypertensive drugs were excluded. The prognostic outcome included death-censored graft failure (DCGF), death-with functioning graft (DWFG), and major adverse cerebrocardiovascular events (MACCEs). RESULTS: We included 8,014 patients without post-transplant hypertension and 6,114 recipients who received treatment for hypertension in the post-transplant period. Those with post-transplant hypertension had a significantly higher risk of DCGF than those without [adjusted hazard ratio (HR) 1.27 (1.09-1.48)]. Post-transplant hypertension patients who required multiple drugs showed a significantly higher risk of DWFG [HR 1.57 (1.17-2.10)] and MACCE [HR 1.35 (1.01-1.81)] than the controls. Among the single-agent users, those who received beta-blockers showed a significantly higher risk of DCGF, although the risks of DWFG or MACCE were similar between the types of antihypertensive agents. Among the multiple agent users, the prognosis was similar, regardless of the prescribed types of antihypertensive agents. CONCLUSION: Post-transplant hypertension was associated with poor post-transplant prognosis, particularly when multiple types of medications were required for treatment. During initial prescription of antihypertensive medication, clinicians may consider that beta-blockers were associated with a higher risk of DCGF in the single-agent users.

Statin initiation and all-cause mortality in incident statin-naïve dialysis patients.

BACKGROUND AND AIMS: Cardiovascular disease is the main cause of death in end-stage kidney disease (ESKD) patients. We aimed to explore the association between statin initiation after starting dialysis and all-cause mortality in statin-naïve ESKD patients. METHODS: We analyzed nationwide claims data of incident dialysis patients from 2010 to 2017 in South Korea. Patients who had previous cardiovascular events or were administered statins before dialysis were excluded. The study group included dialysis patients receiving statins within 1 year after dialysis initiation. The control group was organized after propensity-score matching with age, sex, time of dialysis initiation, and underlying diabetes mellitus and hypertension. The main outcomes were all-cause mortality and major cardiovascular events. RESULTS: We included 1596 patients who started statin treatment and 1:1 matched statin-nonusers. During the 9438 person-year follow-up, 468 deaths and 264 major adverse cardiovascular events (MACEs) occurred. Statin initiation was associated with a reduced risk of all-cause mortality (adjusted hazard ratio (aHR) 0.72, 95% confidence interval (CI) 0.60-0.87, p = 0.001), but not with MACE incidence (aHR 1.06, 95% CI 0.83-1.36, p = 0.62). In particular, patients prescribed the recommended dosage of statins according to the Kidney Disease Improving Global Outcomes guidelines showed the lowest mortality risk (aHR 0.55, 95% CI 0.40-0.75, p < 0.001). CONCLUSIONS: Statin initiation was associated with lower risk of all-cause mortality in statin-naïve ESKD patients. As indication bias may be present in observational study setting, further prospective studies are warranted to validate the association of statin initiation with mortality in incident dialysis cases.

Comparison of renoprotective effects of febuxostat and allopurinol in hyperuricemic patients with chronic kidney disease.

PURPOSE: This study aimed to compare the renoprotective effect between febuxostat and allopurinol in hyperuricemic patients with chronic kidney disease (CKD), about which limited data are available. METHODS: 141 patients with stage 3 CKD and hyperuricemia were followed from June 2005 to April 2018. Thirty patients received febuxostat, 40 allopurinol and 71 conventional CKD management only (control group). We compared the mean serum uric acid levels, estimated glomerular filtration rate (eGFR) changes over time and renal survival time free from predefined renal disease progression among these 3 groups. RESULTS: Overall, mean age was 62.6 ± 13.3 years, baseline eGFR 42.1 ± 8.8 mL/min/1.73 m2, and serum uric acid 8.6 ± 1.5 mg/dL without intergroup difference. During the observation period (55.9 ± 31.8 months), febuxostat group, compared to both allopurinol and control group, had significantly lower mean serum uric acid levels (5.7 ± 1.0 vs. 7.1 ± 1.2 vs. 8.0 ± 0.8 mg/dL, p < 0.001) and maintained significantly higher mean eGFR values consistently for 4 years. Febuxostat group had significantly longer renal survival time free from renal disease progression than allopurinol and control group (87.7 (95% CI 71.2-104.2) vs. 77.6 (95% CI 60.2-94.9) vs. 48.7 (95% CI 39.3-58.1) months, respectively, p < 0.001). Cox proportional hazard model analysis adjusting for potent confounders revealed that febuxostat, with control group as reference, significantly reduced the risk of renal disease progression by 74.3% (hazard ratio 0.257 (95% CI 0.072-0.912), p = 0.036), while allopurinol showed insignificant result. CONCLUSIONS: Febuxostat seems to reduce serum uric acid level and to retard renal disease progression more effectively than allopurinol in hyperuricemic patients with CKD.

Clinical features of active tuberculosis that developed during anti-tumor necrosis factor therapy in patients with inflammatory bowel disease.

BACKGROUND/AIMS: Anti-tumor necrosis factor (TNF) therapy for active ulcerative colitis (UC) and Crohn's disease (CD) is associated with increased risks of tuberculosis (TB) infection. We analyzed the incidence and clinical features of Korean patients with inflammatory bowel disease (IBD) who developed active TB during anti-TNF therapy. METHODS: Ten cases of active TB developed in patients treated with infliximab (n=592) or adalimumab (n=229) for UC (n=160) or CD (n=661) were reviewed. We analyzed demographics, interval between start of anti-TNF therapy and active TB development, tests for latent TB infection (LTBI), concomitant medications, and the details of diagnosis and treatments for TB. RESULTS: The incidence of active TB was 1.2% (10/821): 1.5% (9/592) and 0.4% (1/229) in patients receiving infliximab and adalimumab, respectively. The median time to the development of active TB after initiation of anti-TNF therapy was three months (range: 2-36). Three patients had past histories of treatment for TB. Positive findings in a TB skin test (TST) and/or interferon gamma releasing assay (IGRA) were observed in three patients, and two of them received anti-TB prophylaxis. Two patients were negative by both TST and IGRA. The most common site of active TB was the lungs, and the active TB was cured in all patients. CONCLUSIONS: Active TB can develop during anti-TNF therapy in IBD patients without LTBI, and even in those with histories of TB treatment or LTBI prophylaxis. Physicians should be aware of the potential for TB development during anti-TNF therapy, especially in countries with a high prevalence of TB.

The effect of sequential therapy with lansoprazole and ecabet sodium in treating iatrogenic gastric ulcer after endoscopic submucosal dissection: a randomized prospective study.

OBJECTIVE: Ecabet sodium (ES) is a new non-systemic anti-ulcer agent belonging to the category of gastroprotective agents. In this study we aimed to compare the efficacy of a combination therapy with lansoprazole (LS) followed by ES with LS alone in treating endoscopic submucosal dissection (ESD)-induced iatrogenic gastric ulcers. METHODS: Patients diagnosed with gastric adenomas or early gastric cancer were randomly divided into either the LS group (30 mg once daily for 4 weeks; n = 45) or the LS + ES group (LS 30 mg once daily for one week followed by ES 1500 mg twice daily for 3 weeks; n = 45). Four weeks after ESD, a follow-up endoscopy was conducted to evaluate the proportions of ulcer reduction and ulcer stages in the two groups. RESULTS: In all, 79 patients were included in the final analyses. Both treatment modalities were well-tolerated in most patients, with a drug compliance of over 80%. There were no significant differences between the two groups in terms of the proportions of ulcer reduction (0.9503 ± 0.1215 in the LS group vs 0.9192 ± 0.0700 in the LS + ES group, P = 0.169) or ulcer stage (P = 0.446). The prevalence of adverse events related to drugs and bleeding were also similar between the two groups. CONCLUSION: Sequential therapy with LS + ES is as effective as LS alone against ESD-induced gastric ulcers.

Expression of Immune-Related Genes during Loach (Misgurnus anguillicaudatus) Embryonic and Early Larval Development.

Early life stage mortality in fish is one of the problems faced by loach aquaculture. However, our understanding of immune system in early life stage fish is still incomplete, and the information available is restricted to a few fish species. In the present work, we investigated the expression of immune-related transcripts in loach during early development. In fishes, recombination-activating gene 1 (RAG-1) and sacsin (SACS) have been considered as immunological function. In this study, the expression of the both genes was assessed throughout the early developmental stages of loach using real-time PCR method. maRAG-1 mRNA was first detected in 0 dph, observed the increased mostly until 40 dph. Significant expression of maRAG-1 was detected in 0 to 40 dph. These patterns of expression may suggest that the loach start to develop its function after hatching. On the other hand, maSACS was detected in unfertilized oocyte to molura stages and 0 to 40 dph. maSACS mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred.

Transcriptional Onset of Lysozyme Genes during Early Development in Olive Flounder (Paralichthys olivaceus).

The immune system in teleost fish is not completely developed during embryonic and larval stages, therefore effective innate mechanisms is very important for survival in such an environment. However, the knowledge of the development of immune system assumed to be restricted. In many species, lysozymes have been considered as important genes of the first line immune defense. The early detection of lysozyme mRNA in previous reports, led to the investigation of its presence in oocytes. As a result, c-type lysozyme mRNA transcripts were detected in unfertilized oocytes indicating maternal transfer. Therefore, we investigated the expression patterns of lysozymes in flounder, including the matured oocyte. In our results, c-type lysozyme mRNA was first detected in unfertilized oocyte stage, observed the significantly decreased until hatching stage, and was significantly increased after hatching stage. On the other hand, g-type lysozyme mRNA transcripts were first detected at late neurula stage, and the mRNA level was significantly increased after 20 dph. It may be suggest that maternally supplied mRNAs are selectively degraded prior to the activation of embryonic transcription. This study will be help in understanding the maturation and onset of humoral immunity during development of olive flounder immune system.

RAG-1 and IgM Genes, Markers for Early Development of the Immune System in Olive Flounder, Paralichthys olivaceus.

Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival. However, the knowledge of the development of immune system in fish is limited and in demand now. In vertebrates, recombination-activating gene 1 (RAG-1) and immunoglobulin M (IgM) have been considered as very useful markers of the physiological maturity of the immune system. In this study, the expression of the both genes was assessed throughout the early developmental stages of olive flounder larvae (5-55 dph) and used as markers to follow the development of immune system. RAG-1 and IgM mRNA expression was detectable at 5 dph and remained so until 55 dph. These patterns of expression may suggest that the olive flounder start to develop its function around 5 dph. Tissue distribution was found that both genes mRNAs are only expressed in the immune-related organ such as spleen, kidney and gill. The early detection of IgM mRNA led to the investigation of its presence in oocytes. Both RAG-1 and IgM mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred. The biological significance of such a phenomenon remains to be investigated.

Expression of Vimentin Intermediate Filament for Vascular Development in Olive Flounder (Paralichthys olivaceus).

Cardiovascular system is the primary organ to develop and reach a functional state, which underscores the essential role of the vasculature in the developing embryo. The vasculature is a highly specialized organ that functions in a number of key physiological works including the carrying of oxygen and nutrients to tissues. It is closely involved in the formation of heart, and hence it is essential for survival during the hatching period. The expression of genes involved during vascular development in the olive flounder (Paralichthys olivaceus) in the days after hatching is not fully understood. Therefore, we examined the expression patterns of genes activated during the development of flounder. Microscopic observations showed that formation of blood vessels is related to the expression of the vimentin gene. Also, the temporal expression patterns of this vimentin-like gene in the developmental stages and in the normal tissues of olive flounder. The purpose of this study was to examine the expression patterns of vimentin in normal tissues of the olive flounder and during the development of the vascular system in newly hatched olive flounders and HIF-1 plays a vital role in the formation of blood vessels during development. Vimentin expression was strong at the beginning of the development of blood vessels, and was present throughout all developmental stages. Our findings have important implications with respect to the roles of vimentin and HIF-1 in the development and evolution of the first blood vessels in olive flounder. Further studies are required to elucidate the vimentin-mediated hypoxic response signal transduction and to decipher the functional role of vimentin in developmental stages.

Genetic structure of the Korean black scraper Thamnaconus modestus inferred from microsatellite marker analysis.

The Korean black scraper, Thamnaconus modestus, is one of the most economically important maricultural fish species in Korea. However, the annual catch of this fish has been continuously declining over the past several decades. In this study, the genetic diversity and relationships among four wild populations and two hatchery stocks of Korean black scraper were assessed based on 16 microsatellite (MS) markers. A total of 319 different alleles were detected over all loci with an average of 19.94 alleles per locus. The hatchery stocks [mean number of alleles (N(A)) = 12, allelic richness (A(R)) = 12, expected heterozygosity (He) = 0.834] showed a slight reduction (P > 0.05) in genetic variability in comparison with wild populations (mean N(A) = 13.86, A(R) = 12.35, He = 0.844), suggesting a sufficient level of genetic variation in the hatchery populations. Similarly low levels of inbreeding and significant Hardy-Weinberg equilibrium deviations were detected in both wild and hatchery populations. The genetic subdivision among all six populations was low but significant (overall F(ST) = 0.008, P < 0.01). Pairwise F(ST), a phylogenetic tree, and multidimensional scaling analysis suggested the existence of three geographically structured populations based on different sea basin origins, although the isolation-by-distance model was rejected. This result was corroborated by an analysis of molecular variance. This genetic differentiation may result from the co-effects of various factors, such as historical dispersal, local environment and ocean currents. These three geographical groups can be considered as independent management units. Our results show that MS markers may be suitable not only for the genetic monitoring of hatchery stocks but also for revealing the population structure of Korean black scraper populations. These results will provide critical information for breeding programs, the management of cultured stocks and the conservation of this species.

Expression Analysis of Cathepsin F during Embryogenesis and Early Developmental Stage in Olive Flounder (Paralichthys olivaceus).

Cathepsins are members of the multigene family of lysosomal cysteine proteinases and have regulated function in several life processes. The potential role of cathepsin F cysteine gene was expected as protease in the yolk processing mechanism during early developmental stage, but expression analysis was unknown after fertilization. The alignment analysis showed that amino acid sequence of cathepsin F from olive flounder liver expressed sequence tag (EST) homologous to cathepsin F of other known cathepsin F sequences with 87-98% identity. In this study, we examined the gene expression analysis of cathepsin F in various tissues at variety age flounder. Tissue distribution of the cathepsin F mRNA has been shown to be ubiquitous and constitutive pattern regardless of age in each group, although derived from cDNA library using liver sample. The mRNA level of cathepsin F more increased as developmental proceed during embryogenesis and early developmental stage, especially increased in the blastula, hatching stage and 3 days post hatching (dph). As a result, it may suggest that the proteolysis of yolk proteins (YPs) has been implicated as a mechanism for nutrient supply during early larval stages in olive flounder.

The Expression Analysis of Complement Component C3 during Early Developmental Stages in Olive Flounder (Paralichthys olivaceus).

Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival in such an environment. The key component of innate immune system, C3 is central protein of all activation pathways of the complement system, leading to inflammatory reactions, such as opsonisation, chemotaxis, and cell lysis of pathogens. Although, innate mechanisms is essential for survival in the early stage of development, little is known about defence mechanisms. In this study, the alignment analysis showed that amino acid sequence of C3 from olive flounder liver EST homologous to other known C3 sequences with 73-99% identity. Also, we examined the tissue distribution of olive flounder C3 and analyzed expression pattern from the fertilized egg until 28 days post hatching. As a result, olive flounder C3 mRNA was expressed only in the liver and the mRNA level more increased as developmental proceed during the early stage. These results may suggest that olive flounder C3 plays an important function in the early immune response of olive flounder larvae.

Application of novel polymorphic microsatellite loci identified in the Korean Pacific Abalone (Haliotis diversicolor supertexta (Haliotidae)) in the genetic characterization of wild and released populations.

The small abalone, Haliotis diversicolor supertexta, of the family Haliotidae, is one of the most important species of marine shellfish in eastern Asia. Over the past few decades, this species has drastically declined in Korea. Thus, hatchery-bred seeds have been released into natural coastal areas to compensate for the reduced fishery resources. However, information on the genetic background of the small abalone is scarce. In this study, 20 polymorphic microsatellite DNA markers were identified using next-generation sequencing techniques and used to compare allelic variation between wild and released abalone populations in Korea. Using high-throughput genomic sequencing, a total of 1516 (2.26%; average length of 385 bp) reads containing simple sequence repeats were obtained from 86,011 raw reads. Among the 99 loci screened, 28 amplified successfully, and 20 were polymorphic. When comparing allelic variation between wild and released abalone populations, a total of 243 different alleles were observed, with 18.7 alleles per locus. High genetic diversity (mean heterozygosity = 0.81; mean allelic number = 15.5) was observed in both populations. A statistical analysis of the fixation index (F(ST)) and analysis of molecular variance (AMOVA) indicated limited genetic differences between the two populations (F(ST) = 0.002, p > 0.05). Although no significant reductions in the genetic diversity were found in the released population compared with the wild population (p > 0.05), the genetic diversity parameters revealed that the seeds released for stock abundance had a different genetic composition. These differences are likely a result of hatchery selection and inbreeding. Additionally, all the primer pair sets were effectively amplified in another congeneric species, H. diversicolor diversicolor, indicating that these primers are useful for both abalone species. These microsatellite loci may be valuable for future aquaculture and population genetic studies aimed at developing conservation and management plans for these two abalone species.

Development of microsatellite markers for the Korean Mussel, Mytilus coruscus (Mytilidae) using next-generation sequencing.

Mytilus coruscus (family Mytilidae) is one of the most important marine shellfish species in Korea. During the past few decades, this species has become endangered due to the loss of habitats and overfishing. Despite this species' importance, information on its genetic background is scarce. In this study, we developed microsatellite markers for M. coruscus using next-generation sequencing. A total of 263,900 raw reads were obtained from a quarter-plate run on the 454 GS-FLX titanium platform, and 176,327 unique sequences were generated with an average length of 381 bp; 2569 (1.45%) sequences contained a minimum of five di- to tetra-nucleotide repeat motifs. Of the 51 loci screened, 46 were amplified successfully, and 22 were polymorphic among 30 individuals, with seven of trinucleotide repeats and three of tetranucleotide repeats. All loci exhibited high genetic variability, with an average of 17.32 alleles per locus, and the mean observed and expected heterozygosities were 0.67 and 0.90, respectively. In addition, cross-amplification was tested for all 22 loci in another congener species, M. galloprovincialis. None of the primer pairs resulted in effective amplification, which might be due to their high mutation rates. Our work demonstrated the utility of next-generation 454 sequencing as a method for the rapid and cost-effective identification of microsatellites. The high degree of polymorphism exhibited by the 22 newly developed microsatellites will be useful in future conservation genetic studies of this species.

Comparison between wild and hatchery populations of Korean pen shell (Atrina pectinata) using microsatellite DNA markers.

Pen shell (Atrina pectinata) is a popular food source with a high commercial value in a number of Asian Pacific areas. The natural A. pectinata population has been declining continuously over the past several decades. Microsatellite DNA markers are a useful DNA-based tool for monitoring the genetic variation of pen shell populations. In this study, 20 polymorphic microsatellite (MS) DNA markers were identified from a partial genomic pen shell DNA library enriched in CA repeats, and used to compare allelic variation between wild and hatchery pen shell populations in Korea. A total of 438 alleles were detected at the 20 MS loci in the two populations. All loci were easily amplified and demonstrated allelic variability, with the number of alleles ranging from 5 to 35 in the wild population and from 5 to 22 in the farmed population. The average observed and expected heterozygosities were 0.69 and 0.82, respectively, in the hatchery samples and 0.69 and 0.83, respectively, in the wild samples. Statistical analysis of fixation index (F(ST)) and analysis of molecular variance (AMOVA) showed minor, but significant, genetic differences between the wild and hatchery populations (F(ST) = 0.0106, CI(95%) = 0.003-0.017). These microsatellite loci may be valuable for future aquaculture and population genetic studies for developing conservation and management plans. Further studies with additional pen shell samples are needed to conclusively determine the genetic diversity between the wild and hatchery populations.

Genetic characterization of five hatchery populations of the Pacific Abalone (Haliotis discus hannai) using microsatellite markers.

The Pacific abalone, Haliotis discus hannai, is a popular food in Eastern Asia. Aquacultural production of this species has increased because of recent resource declines, the growing consumption, and ongoing government-operated stock release programs. Therefore, the genetic characterization of hatchery populations is necessary to maintain the genetic diversity of this species and to develop more effective aquaculture practices. We analyzed the genetic structures of five cultured populations in Korea using six microsatellite markers. The number of alleles per locus ranged from 15 to 64, with an average of 23.5. The mean observed and expected heterozygosities were 0.797 and 0.904, respectively. The inbreeding coefficient F(IS) ranged from 0.054 to 0.184 (mean F(IS) = 0.121 ± 0.056). The genetic differentiation across all populations was low but significant (overall F(ST) = 0.009, P < 0.01). Pairwise multilocus F(ST) tests, estimates of genetic distance, and phylogenetic and principal component analyses did not show a consistent relationship between geographic and genetic distances. These results could reflect extensive aquaculture, the exchange of breeds and eggs between hatcheries and/or genetic drift due to intensive breeding practices. Thus, for optimal resource management, the genetic variation of hatchery stocks should be monitored and inbreeding controlled within the abalone stocks that are being released every year. This genetic information will be useful for the management of both H. discus hannai fisheries and the aquaculture industry.

Novel polymorphic microsatellite loci for the Korean Black Scraper (Thamnaconus modestus), and their application to the genetic characterization of wild and farmed populations.

In this study, we developed 20 polymorphic microsatellite markers for the Korean black scraper, Thamnaconus modestus (Günther, 1877), Monacanthidae, and used them to compare allelic variation between wild and hatchery populations in Korea. All loci were readily amplified and demonstrated allelic variability, with the number of alleles ranging from 5-35 in the wild population and 5-22 in the farmed population. The average observed and expected heterozygosities were estimated, respectively, as 0.74 and 0.80 in the hatchery samples and 0.78 and 0.81 in the wild ones. These results indicate lower genetic variability in the hatchery population than in the wild population and minor, but significant, genetic differentiation between the two populations (F(ST) = 0.005, P < 0.01). Additionally, cross-amplification was tested in another monacanthid species, Stephanolepis cirrhifer; many loci were found that yielded useful information. The high degree of polymorphism exhibited by the 20 microsatellites will be useful in future aquaculture and population genetic studies for developing conservation and management plans.

Wild and hatchery populations of Korean starry flounder (Platichthys stellatus) compared using microsatellite DNA markers.

Starry flounder (Platichthys stellatus) is an important sport and food fish found around the margins of the North Pacific. Aquaculture production of this species in Korea has increased because of its commercial value. Microsatellite DNA markers are a useful DNA-based tool for monitoring the genetic variation of starry flounder populations. In this study, 12 polymorphic microsatellite DNA markers were identified from a partial genomic starry flounder DNA library enriched in CA repeats, and used to compare allelic variation between wild and hatchery starry flounder populations in Korea. All loci were readily amplified and demonstrated high allelic diversity, with the number of alleles ranging from 6 to 18 in the wild population and from 2 to 12 in the farmed population. A total of 136 alleles were detected at the 12 microsatellite loci in the two populations. The mean observed and expected heterozygosities were 0.62 and 0.68, respectively, in the hatchery samples and 0.67 and 0.75, respectively, in the wild samples. These results indicate lower genetic variability in the hatchery population as compared to the wild population. Significant shifts in allelic frequencies were detected at eight loci, which resulted in a small but significant genetic differences between the wild and hatchery populations (F(ST) = 0.043, P < 0.05). Further studies with additional starry flounder sample collections are needed for comprehensive determinations of the genetic varieties between the wild and hatchery populations. These microsatellite loci may be valuable for future population genetic studies, monitoring the genetic variation for successful aquaculture management and the preservation of aquatic biodiversity.