• Animal cells and systems
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• v.16 no.2
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• pp.145-153
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• 2012

The pear psylla, $Cacopsylla$ $pyricola$ (Hemiptera: Psyllidae), is a serious insect pest of commercial pear crops. The species, which resides on pear trees throughout its life cycle, is rapidly spreading in some regions of the world. The population genetic structure of the species collected from several pear orchards in Korea was studied to understand the nature of dispersal and field ecology of the species. The 658-bp region of mitochondrial COI gene and the 716-bp long complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA were sequenced. Unlike other previously studied insect pests, the COI-based genetic diversity of the pear psylla was extremely low (maximum sequence divergence of 0.15%). This finding allowed us to conclude that the species may have been introduced in Korea relatively recently. ITS2 sequence-based analyses of phylogeny, population differentiation, gene flow, and hierarchical population structure all concordantly suggested that the pear psylla populations in Korea are neither genetically isolated nor hampered for gene flow. These genetic data are concordant with the dispersal of an overwintering winterform morph outside the non-pear habitat in the fall.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.211-226
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• 2000

Genetic divergence and phylogenetic relationships among the major Korean fireflies (Hotaria papariensis, Luciola lateralis, and Pyrocoelia rufa) were studied. A portion of mitochondrial COI (403 bp) and 165 rRNA (490~504 bp) genes were sequenced, and the GenBank-registered, homologous 165 rRNA sequences of Japanese fireflies were compared (27 species of Lampyridae, one of Lycidae, and one of Rhgophthalmidae). Greatest DNA and/or amino acid sequence divergence was found when P rufa, belonging to Lampyrinae was compared with H. papariensis and L. lateralis, both belong-ing to Luciolinae, confirming the current taxonomic status of the species. In the PAUP and PHYLIP analyses with 165 rRNA data, grouping of the two geographic samples of H. papariensis with H. tsushimana validate the use of generic name, Hotaria. Nevertheless, lack of sister-group relationship of the two geographic samples of H. papariensis renders further investigation on this group . Although the Korean and Japanese L. lateralis formed a strong monophyletic group, a substantial genetic differentiation was detected between them (2.9% of 165 rRNA gene sequence divergence). Finally, the geographic samples of Korean p. rufa strongly formed a group with Japanese p. rufa, warranting the use of generic name, Pyrocoelia, but the genetic distance observed between the Cheju-Island individual and all others requires further investigation on this subject. Summarized, this study supports the current taxonomic status of the Korean fireflies in that each respectively formed a strong monophyletic group with its own species or genus.

• Journal of Korean Society of Forest Science
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• v.90 no.2
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• pp.169-175
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• 2001

Genomic DNAs were extracted from the leaves of 182 ginkgo trees (Ginkgo biloba L.) planted in 6 regions and subjected to the analysis of both I-SSR and RAPD markers. A total of 227 amplicon variants were generated by PCR using 15 I-SSR primers and 67 amplicons by PCR with 5 RAPD primers. Levels of genetic diversity within 6 populations were turned out to be similar (Shannon's Index, I-SSR : 0.35~0.40; mean of 0.38, RAPD : 0.31~0.38; mean of 0.35, combined : 0.35~0.40; mean of 0.37). Ranks of the level of genetic diversity estimated from I-SSR, RAPD, and combined data were not coincided each other. Majority of genetic diversity was allocated among individuals within populations (I-SSR : 94.31%, RAPD : 93.62%, combined : 93.57%), which resulted in pretty low level of population differentiation. Genetic differentiation between male and female groups was turned out to be quite low (I-SSR : 0.03, RAPD : 0.091, combined : 0.043), which slightly fluctuated when analysis was restricted to the data obtained from 3 regions where both male and female trees were sampled (I-SSR : 0.038, RAPD : 0.084, combined : 0.047). Genetic relationships among the populations, reconstructed by UPGMA, were not coincided with geographic affinity, which might be resulted from sharing of seed sources in some regions. Whereas independent cluster analyses with I-SSR data and RAPD data, respectively, reclassified by sexes revealed two sexual groups in which all the male and the female populations were clustered together, cluster analysis with combined data did not show clear sexual grouping.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2431-2440
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• 2015

Background: Registry data from four major public hospitals indicate trends in clinical care and survival from colorectal cancer over three decades, from 1980 to 2010. Materials and Methods: Kaplan-Meier productlimit estimates and Cox proportional hazards models were used to investigate disease-specific survival and multiple logistic regression analyses to explore first-round treatment trends. Results: Five-year survivals increased from 48% for 1980-1986 to 63% for 2005-2010 diagnoses. Survival increases applied to each ACPS stage (Australian Clinico-Pathological Stage), and particularly stage C (an increase from 38% to 68%). Risk of death from colorectal cancer halved (hazards ratio: 0.50 (0.45, 0.56)) over the study period after adjusting for age, sex, stage, differentiation, primary sub-site, health administrative region, and measures of socioeconomic status and geographic remoteness. Decreases in stage were not observed. Survivals did not vary by sex or place of residence, suggesting reasonable equity in service access and outcomes. Of staged cases, 91% were treated surgically with lower surgical rates for older ages and more advanced stage. Proportions of surgical cases having adjuvant therapy during primary courses of treatment increased for all stages and were highest for stage C (an increase from 5% in 1980-1986 to 63% for 2005-2010). Radiotherapy was more common for rectal than colonic cases. Proportions of rectal cases receiving radiotherapy increased, particularly for stage C where the increase was from 8% in 1980-1986 to 60% in 2005-2010. The percentage of stage C colorectal cases less than 70 years of age having systemic therapy as part of their first treatment round increased from 3% in 1980-1986 to 81% by 1995-2010. Based on survey data on uptake of adjuvant therapy among those offered this care, it is likely that all these younger patients were offered systemic treatment. Conclusions: We conclude that pronounced increases in survivals from colorectal cancer have occurred at major public hospitals in South Australia due to increases in stage-specific survivals. Use of adjuvant therapies has increased and the patterns of change accord with clinical guideline recommendations. Reasons for sub-optimal use of radiotherapy for rectal cases warrant further investigation, including the potential for limited rural access to impede uptake of treatments at metropolitan-based radiotherapy centres.

• Korean Journal of Plant Taxonomy
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• v.45 no.3
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• pp.254-261
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• 2015

Genetic variations of Abies koreana and Abies nephrolepis were assessed using two mitochondrial DNA regions (nad5 intron 4 and nad5 intron 1) for 16 natural populations to understand their phylogeographical history. Seven polymorphic sites of the two combined regions resulted in the resolution of four haplotypes (M1-M4). The average gene diversity within the population ($H_S$) was 0.098, the total gene diversity ($H_T$) was 0.620, and the interpopulation differentiation was $G_{ST}=0.841$, $N_{ST}=0.849$. The populations were divided into three groups (northern area, central area, southern area) according to their geographic locations. The populations of the northern and southern areas were mostly fixed for M1 and M2, respectively. The populations of the central area showed the highest levels of gene diversity ($H_T=0.654$) due to introgression from the northern area and southern area. The presence of a single mtDNA haplotype in the southern area suggests that current widespread populations have expanded to the central area from a specific refugium population after the last glacial period.

• Korean Journal of Plant Taxonomy
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• v.43 no.4
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• pp.267-273
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• 2013

This study employed inter-simple-sequence repeat (ISSR) to assess genetic variation among 189 individuals representing 10 populations (nine in Korea and one in Japan) of Millettia japonica, which has recently been lifted from the endangered species of Korea. The calculated Shannon's information index value (I = 0.2689) of the species was appreciable and was higher than other endangered leguminous woody taxa. Gochang (I = 0.2968), Namhae (I = 0.2951), and Mt. Toham (I = 0.2823) populations showed relatively high genetic diversity, whereas the Kyushu (in Japan) population (I = 0.2487) exhibited the lowest. The results of an analysis of molecular variance indicated that 86.49% of the diversity was attributed to within populations, and 13.51% to differences among populations, suggesting that M. japonica populations do not have significant geographic differentiation and that the gene flow between populations exists to some extent (Nm = 1.8446). Continuous habitat monitoring should be conducted to conserve genetic diversity of M. japonica, particularly for those populations with relatively high genetic diversity. Selection of many individuals from the populations in Gochang, Namhae, and Mt. Toham is thought to be an appropriate strategy for ex situ conservation of M. japonica in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1691-1699
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• 2018

Objective: In Korea, there are three main cattle breeds, which are distinguished by coat color: Brown Hanwoo (BH), Brindle Hanwoo (BRH), and Jeju Black (JB). In this study, we sought to compare the genetic diversity and divergence among there Korean cattle breeds using a BovineHD chip genotyping array. Methods: Sample data were collected from 168 cattle in three populations of BH (48 cattle), BRH (96 cattle), and JB (24 cattle). The single-nucleotide polymorphism (SNP) genotyping was performed using the Illumina BovineHD SNP 777K Bead chip. Results: Heterozygosity, used as a measure of within-breed genetic diversity, was higher in BH (0.293) and BRH (0.296) than in JB (0.266). Linkage disequilibrium decay was more rapid in BH and BRH than in JB, reaching an average $r^2$ value of 0.2 before 26 kb in BH and BRH, whereas the corresponding value was reached before 32 kb in JB. Intra-population, interpopulation, and Fst analyses were used to identify candidate signatures of positive selection in the genome of a domestic Korean cattle population and 48, 11, and 11 loci were detected in the genomic region of the BRH breed, respectively. A Neighbor-Joining phylogenetic tree showed two main groups: a group comprising BH and BRH on one side and a group containing JB on the other. The runs of homozygosity analysis between Korean breeds indicated that the BRH and JB breeds have high inbreeding within breeds compared with BH. An analysis of differentiation based on a high-density SNP chip showed differences between Korean cattle breeds and the closeness of breeds corresponding to the geographic regions where they are evolving. Conclusion: Our results indicate that although the Korean cattle breeds have common features, they also show reliable breed diversity.

• Journal of Gastric Cancer
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• v.17 no.2
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• pp.132-144
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• 2017

Purpose: To identify baseline prognostic factors for survival in patients with disease progression, during or after chemotherapy for the treatment of advanced gastric or gastroesophageal junction (GEJ) cancer. Materials and Methods: We pooled data from patients randomized between 2009 and 2012 in 2 phase III, global double-blind studies of ramucirumab for the treatment of advanced gastric or GEJ adenocarcinoma following disease progression on first-line platinum- and/or fluoropyrimidine-containing therapy (REGARD and RAINBOW). Forty-one key baseline clinical and laboratory factors common in both studies were examined. Model building started with covariate screening using univariate Cox models (significance level=0.05). A stepwise multivariable Cox model identified the final prognostic factors (entry+exit significance level=0.01). Cox models were stratified by treatment and geographic region. The process was repeated to identify baseline prognostic quality of life (QoL) parameters. Results: Of 1,020 randomized patients, 953 (93%) patients without any missing covariates were included in the analysis. We identified 12 independent prognostic factors of poor survival: 1) peritoneal metastases; 2) Eastern Cooperative Oncology Group (ECOG) performance score 1; 3) the presence of a primary tumor; 4) time to progression since prior therapy <6 months; 5) poor/unknown tumor differentiation; abnormally low blood levels of 6) albumin, 7) sodium, and/or 8) lymphocytes; and abnormally high blood levels of 9) neutrophils, 10) aspartate aminotransferase (AST), 11) alkaline phosphatase (ALP), and/or 12) lactate dehydrogenase (LDH). Factors were used to devise a 4-tier prognostic index (median overall survival [OS] by risk [months]: high=3.4, moderate=6.4, medium=9.9, and low=14.5; Harrell's C-index=0.66; 95% confidence interval [CI], 0.64-0.68). Addition of QoL to the model identified patient-reported appetite loss as an independent prognostic factor. Conclusions: The identified prognostic factors and the reported prognostic index may help clinical decision-making, patient stratification, and planning of future clinical studies.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.51-58
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• 2014

Genetic diversity and genetic structures were estimated in seven natural populations of Phellodendron amurense Rupr in South Korea using ISSR markers. The average of polymorphic loci per primer and the proportion of polymorphic loci per population were 4.5 and 78.8% respectively with total 27 polymorphic loci from 6 ISSR primers. The Shannon's diversity index(I) was 0.421 and the expected heterozygosity($H_e$) was 0.285, which was similar to the heterozygosity (hs =0.287) inferred by Bayesian method. In AMOVA, 7.6% of total genetic variation in the populations was resulted from the genetic difference among populations and the other 92.4% was resulted from the difference among individuals within populations. Genetic differentiation(${\theta}^{II}$) and inbreeding coefficient(f) for total population were estimated to be 0.066 and 0.479 by Bayesian method respectively. In Bayesian clustering analysis, seven populations were assigned into three groups. This result was similar to the results of genetic relationships by UPGMA and PCA. The first group included Hwachoen, Gapyeong, Bongpyeong and Yongpyeong population, and the second included two populations in Sancheong region. Muju population was discretely assigned into the third group in spite of the geographically short distance from the Sancheong region. There was no significant correlation between genetic relationship and geographic distribution among populations in Mantel's test. For conservation of the phellodendron trees, it would be effective to consider the findings resulted from this study with ecological traits and life histories of this species.

• Korean Journal of Ornithology
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• v.25 no.2
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• pp.117-125
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• 2018

The Grey-capped greenfinch (Chloris sinica) is a polytypic species that exhibits complicated geographical variation in morphology. This study provides an intraspecific phylogeographic variability of C. sinica populations in Korea with their morphometric data. The observed morphometric variations were that Ulleung island population was morphologically distinct in bill length and depths as compared to the mainland populations. Phylogenetic relationships among mitochondrial COX1 regions provided evidence for genetic differentiation between Ulleung and mainland populations. However, their genetic distances and nucleotide diversities were very low, highlighting their recent divergence. The needs for additional research is heightened to substantiate if the genetic clines in different localities may arise in C. sinica subspecies, each of which could have different breeding and wintering habitats, distribution patterns, and migration pathways.