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PubMed2005

Is antibody clustering predictive of clinical subsets and damage in systemic lupus erythematosus?

OBJECTIVE: To examine autoantibody clusters and their associations with clinical features and organ damage accrual in patients with systemic lupus erythematosus (SLE). METHODS: The study group comprised 1,357 consecutive patients with SLE who were recruited to participate in a prospective longitudinal cohort study. In the cohort, 92.6% of the patients were women, the mean +/- SD age of the patients was 41.3 +/- 12.7 years, 55.9% were Caucasian, 39.1% were African American, and 5% were Asian. Seven autoantibodies (anti-double-stranded DNA [anti-dsDNA], anti-Sm, anti-Ro, anti-La, anti-RNP, lupus anticoagulant (LAC), and anticardiolipin antibody [aCL]) were selected for cluster analysis using the K-means cluster analysis procedure. RESULTS: Three distinct autoantibody clusters were identified: cluster 1 (anti-Sm and anti-RNP), cluster 2 (anti-dsDNA, anti-Ro, and anti-La), and cluster 3 (anti-dsDNA, LAC, and aCL). Patients in cluster 1 (n = 451), when compared with patients in clusters 2 (n = 470) and 3 (n = 436), had the lowest incidence of proteinuria (39.7%), anemia (52.8%), lymphopenia (33.9%), and thrombocytopenia (13.7%). The incidence of nephrotic syndrome and leukopenia was also lower in cluster 1 than in cluster 2. Cluster 2 had the highest female-to-male ratio (22:1) and the greatest proportion of Asian patients. Among the 3 clusters, cluster 2 had significantly more patients presenting with secondary Sjögren's syndrome (15.7%). Cluster 3, when compared with the other 2 clusters, consisted of more Caucasian and fewer African American patients and was characterized by the highest incidence of arterial thrombosis (17.4%), venous thrombosis (25.7%), and livedo reticularis (31.4%). By using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index, the greatest frequency of nephrotic syndrome (8.9%) was observed in patients in cluster 2, whereas cluster 3 patients had the highest percentage of damage due to cerebrovascular accident (12.8%) and venous thrombosis (7.8%). Osteoporotic fracture (11.9%) was also more common in cluster 3 than in cluster 2. CONCLUSION: Autoantibody clustering is a valuable tool to differentiate between various subsets of SLE, allowing prediction of subsequent clinical course and organ damage.

Adult↗

PubMed2005

Is "relationship fear" unique to Japan? Symptom factors and patient clusters of social anxiety disorder among the Japanese clinical population.

BACKGROUND: There have been only a limited number of cross-cultural studies of social anxiety disorder (SAD), especially as diagnosed with modern operationalized diagnostic criteria and as measured with recently developed assessment instruments. We examined the symptomatological structure and clinical subtypes of patients with DSM-IV SAD among the Japanese clinical population. METHODS: We performed confirmatory and exploratory factor analyses of the joint Social Interaction Anxiety Scale and Social Phobia Scale from 149 psychiatric patients diagnosed with SAD. Based on the derived symptom factors, we further ran cluster analysis to identify patient subgroups. RESULTS: Factor analyses revealed three factors which were named "scrutiny fears", "conversation fears" and "relationship fears". The first two appeared common to Western clinical populations but the third appeared unique to the Japanese. Cluster analysis based on these three factor scores yielded three subgroups, which were externally validated and which overall corresponded with mild, moderate and pervasive subtypes of social phobia. LIMITATIONS: Both factor analysis and cluster analysis employed in the present study are exploratory in nature. Further empirical examination in different settings and cultures is necessary to provide definitive answers. CONCLUSIONS: It is suggested that we may need three symptom subscales and three subtypes in order to better account for cultural variations in the presentation of SAD.

Adolescent↗

PubMed2006

Identification of new participants in the rainbow trout (Oncorhynchus mykiss) oocyte maturation and ovulation processes using cDNA microarrays.

BACKGROUND: The hormonal control of oocyte maturation and ovulation as well as the molecular mechanisms of nuclear maturation have been thoroughly studied in fish. In contrast, the other molecular events occurring in the ovary during post-vitellogenesis have received far less attention. METHODS: Nylon microarrays displaying 9152 rainbow trout cDNAs were hybridized using RNA samples originating from ovarian tissue collected during late vitellogenesis, post-vitellogenesis and oocyte maturation. Differentially expressed genes were identified using a statistical analysis. A supervised clustering analysis was performed using only differentially expressed genes in order to identify gene clusters exhibiting similar expression profiles. In addition, specific genes were selected and their preovulatory ovarian expression was analyzed using real-time PCR. RESULTS: From the statistical analysis, 310 differentially expressed genes were identified. Among those genes, 90 were up-regulated at the time of oocyte maturation while 220 exhibited an opposite pattern. After clustering analysis, 90 clones belonging to 3 gene clusters exhibiting the most remarkable expression patterns were kept for further analysis. Using real-time PCR analysis, we observed a strong up-regulation of ion and water transport genes such as aquaporin 4 (aqp4) and pendrin (slc26). In addition, a dramatic up-regulation of vasotocin (avt) gene was observed. Furthermore, angiotensin-converting-enzyme 2 (ace2), coagulation factor V (cf5), adam 22, and the chemokine cxcl14 genes exhibited a sharp up-regulation at the time of oocyte maturation. Finally, ovarian aromatase (cyp19a1) exhibited a dramatic down-regulation over the post-vitellogenic period while a down-regulation of Cytidine monophosphate-N-acetylneuraminic acid hydroxylase (cmah) was observed at the time of oocyte maturation. CONCLUSION: We showed the over or under expression of more that 300 genes, most of them being previously unstudied or unknown in the fish preovulatory ovary. Our data confirmed the down-regulation of estrogen synthesis genes during the preovulatory period. In addition, the strong up-regulation of aqp4 and slc26 genes prior to ovulation suggests their participation in the oocyte hydration process occurring at that time. Furthermore, among the most up-regulated clones, several genes such as cxcl14, ace2, adam22, cf5 have pro-inflammatory, vasodilatory, proteolytics and coagulatory functions. The identity and expression patterns of those genes support the theory comparing ovulation to an inflammatory-like reaction.

Animals↗

PubMed1994

Morphological analysis of cervical vertebrae in ataxic foals.

Morphological differences between cervical vertebrae were statistically analyzed in ataxic foals to clarify abnormal structural factors in the pathogenesis of this problem. At first, multiple regression analysis and cluster analysis were performed with 28 variables in C3-C7 of 39 control foals without lameness. As a result, there were no sex differences in the growth of all cervical vertebral sites, and the most suitable categorization of the age of the foals was 3 clusters of 8 months old or younger, 9-12 months old and 13 months old or older in any sites in the cervical vertebrae. Twenty-eight ataxic and 19 control foals at the age of 13 months or older were then used for discriminant analysis with 20 variables. As a result, 1-7 variables on C3-C7 were selected for sufficient discrimination, in which the heights of the cranial and caudal orifices of the spinal canal, longitudinal length of the vertebral head and height of the vertebral fossa strongly contributed to the discrimination of all the cervical vertebrae. In addition, the widths and longitudinal diameters of the articular processes on articular surfaces strongly contributed to the discrimination of the caudal region of the neck. In conclusion, it was suggested that the lesion in the cervical spinal cord observed in ataxic foals was caused by morphological abnormalities including osteochondrosis and subsequent degenerative joint disease in the cervical vertebrae.

Animals↗

PubMed1985

Quantitative analyses of axonal endings in the central nucleus of the inferior colliculus and distribution of 3H-labeling after injections in the dorsal cochlear nucleus.

Quantitative analyses of electron microscopic (EM) autoradiographs were used to identify the afferents from the dorsal cochlear nucleus in the central nucleus of the inferior colliculus (IC) in the cat. In order to localize the sources of radioactivity, material from axonal transport experiments was analyzed by means of a hypothetical grain procedure which takes the cross-scatter of beta particles into account. Measurements of the synaptic vesicles in axonal endings and a cluster analysis were used to identify different groups of endings. In order to determine which types of endings arise in the dorsal cochlear nucleus, axonal endings labeled after axonal transport and unlabeled endings were characterized and compared to the groups defined by the cluster analysis. Axonal endings with round synaptic vesicles were labeled with more than 2 grains/micron2 which was about 30% of the radioactivity in the central nucleus of the IC. This was six to seven times greater than if the radioactivity had been randomly distributed. Other tissue compartments usually had less radioactivity. Some myelinated and unmyelinated axons were labeled, but, as a group they had lower amounts of radioactivity than predicted by random labeling. In most cases, only low levels of activity were found in glial and postsynaptic structures. Five groups of axonal endings in the medial part of the central nucleus were identified by an analysis which clustered similar types of endings. The variance of the longest axis, the mean diameter, the variance of area, and the mean area of the synaptic vesicles were the variables most useful in distinguishing these five groups. Axonal endings with round synaptic vesicles were classified as either small, or large, or very large, while endings with pleomorphic vesicles were either large or small. Using measurements of the cross-sectional diameter of dendritic microtubules, samples of digitized axonal endings from normal and experimental cases were normalized and could be compared directly to the groups defined by the cluster analysis. Microtubules were 21.7 nm (+/- 1.6) in average diameter. After injections of 3H-leucine and/or proline in the dorsal cochlear nucleus, most of the labeled endings in the IC contained small, round vesicles (less than 47 nm in diameter) although a very small number of endings with large, round vesicles also were labeled.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2001

Statistical analysis of measures of arousal in ovariectomized female mice.

In preparation for evaluating hormone effects and hormone receptor gene influences on fundamental processes of behavioral arousal, we subjected 48 ovariectomized female mice to a rigid protocol of several tests bearing on arousal concepts. The central hypothesis was that results would organize themselves according to capacities for sensory alertness, motor activity, and emotional reactivity. The large table of across-mouse correlation was subjected to factor analysis and cluster analysis. Results provided evidence for a general arousal (one-factor solution) which, however, accounted for only 29.72% of the variance. Four-factor (72.03%) matched four-cluster and six-factor (84.38%) matched six-cluster lineups of behavior components quite well, but did not conform to the main hypothesis; e.g., home cage exploration frequency and duration variables did not covary, and locomotor wheel activity grouped with fear indices. Besides providing a baseline for ongoing estrogen/thyroid and related genetic experiments, this statistical approach should be useful for a variety of hormonal studies of complex behaviors in mice.

Animals↗

PubMed2005

Analysis of clusters and uniformity of distribution of states of polarization on the Poincaré sphere.

An analysis of the clusters and the uniformity of distribution of states of polarization on the surface of a Poincaré sphere generated by rotating wave plates is given. The analysis of clusters of the states of polarization is based on a spherical radial distribution function. For uniform analysis of the distribution, two methods are proposed. The first method is based on calculation of the correlation coefficient; the second method is based on calculation of the angles between pairs of the states of polarization on the Poincaré sphere. For polarization scramblers consisting of eight or more rotating wave plates, nonclustered and near-uniform distribution of states of polarization is obtained.

Journal Article↗

PubMed2007

Multivariate data analysis of pollutant profiles: PCB levels across Europe.

It is not always recognised that standard multivariate analyses applied to pollution profile data (i.e. where data are relative amounts of pollutants expressed as proportions of their total) give rise to problems in the analysis and interpretation of results: a simple solution is to carry out analyses on log-ratios of proportions. However, while solving many problems, this approach is very sensitive to the issue of values below detection limits. These approaches have been applied to a dataset of the levels of 29 PCB congeners in ambient air samples across Europe during the summer of 2002. Multivariate descriptive methods (principal component analysis and cluster analysis) and inferential techniques (multivariate ANOVA, multiple linear and logistic regression) and graphical tools (2D and 3D plots, principal components plots, biplots and triangular diagrams) were used to analyse the proportions of five PCB homologues (tri-hepta). These established that there was considerable difference in the pollution profiles of the 71 samples: the greatest variation was between samples with differing ratios of tri-hexa and tri-hepta PCB homologues, and the samples showed little sign of consistent clusters. There was a significant difference between typical profiles from rural and urban areas such that urban samples (and those with high total PCBs) had higher proportions of tetra- and tri-PCBs compared to hexa- and hepta-PCBs.

Analysis of Variance↗

PubMed2000

Analysis of clustered firing patterns in synaptically coupled networks of oscillators.

Oscillators in networks may display a variety of activity patterns. This paper presents a geometric singular perturbation analysis of clustering, or alternate firing of synchronized subgroups, among synaptically coupled oscillators. We consideroscillators in two types of networks: mutually coupled, with all-to-all inhibitory connections, and globally inhibitory, with one excitatory and one inhibitory population of oscillators, each of arbitrary size. Our analysis yields existence and stability conditions for clustered states, along with formulas for the periods of such firing patterns. By using two different approaches, we derive complementary conditions, the first set stated in terms of time lengths determined by intrinsic and synaptic properties of the oscillators and their coupling and the second set stated in terms of model parameters and phase space structures directly linked to parameters. These results suggest how biological components may interact to produce the spindle sleep rhythm in thalamocortical networks.

Cluster Analysis↗

PubMed2005

Standardized psychological evaluation pre- and posttransplantation: a new option.

A multicenter study was undertaken involving three teams in Italy to obtain a homogeneous psychological evaluation of patients needing organ transplantations. After a preliminary formulation of a common questionnaire individualizing 22 items, yielding a final score from 0 to 44, 294 forms were analyzed for correlations between variables. The sample responses were related to individual variables as well as by cluster analysis to aggregate typical profiles. Clustering of variables was observed in three areas that showed two variables (no. 6, "ongoing psychotic disturbances" and no. 10 "drugs") to be separate. Area 1 ("psychopathology") highlights psychic disturbances, cognitive disorders, and unhealthy behavioral styles; area 2 ("anxia") correlates anxious symptoms to pretransplant examinations and waiting time; area 3 ("depression") ties personal emotional resources and affective factors. Cluster analysis of the sample identified four groups: Group 1 (16.6%) "at risk;" mean score 25.2 (range 16-31); Group 2 (21.7%) "intermediate-at risk," mean score 32 (range 25-38); Group 3 (29.6%) "intermediate-ideal," mean score 35.3 (range 26-40); and Group 4 (31.9%) "ideal candidate," mean score 40.7 (range 36-44). The two "intermediate" groups were studied for mean values for area 1; namely, a cut-off value of 1.78 constituted a better or worse prognostic factor to assign the patient to either Group 2 or 3. Using a uniform method of psychological evaluation before transplantation reduced single operator subjectivity, obtaining comparable results in different transplant centers and allowing planning interventions for at-risk patients.

Cluster Analysis↗

PubMed2001

Clinical subtypes of schizophrenic disorders: a cluster analytic study.

Two hundred and fifty-five psychiatric inpatients with a definite diagnosis of DSM-IV schizophrenic disorder were examined by means of the Structured Clinical Interview and rated on the 30 main items of the Positive and Negative Syndrome Scale (PANSS). Patients' scores were subjected to a cluster analysis, using Ward's method. Cluster analysis indicated the existence of five groups. The first group (n = 46) comprised patients with overall psychopathology of minimal severity, the second group (n = 39) patients with severe positive symptoms along with symptoms of psychomotor excitement, the third group (n = 58) patients with severe positive psychopathology only, the fourth group (n = 34) patients with severe positive negative depressive and cognitive symptoms and, finally, the fifth group (n = 78) patients with severe negative symptoms only. Patients in the first and third groups were older and their illnesses were of longer duration compared to those of the remaining groups. With respect to DSM-IV clinical types of schizophrenic disorders, the paranoid type predominated in the second and the third groups, whereas the disorganized and catatonic types were markedly overpresented in the fifth group.

Acute Disease↗

PubMed2006

[Characterization by pulsed-field gel electrophoresis of Salmonella typhimurium isolates recovered in the acute diarrheal disease surveillance program in Colombia, 1997-2004].

INTRODUCTION: In Colombia Salmonella Typhimurium is the second most frequently isolated Salmonella serotype (after S. Enteritidis) from human clinical samples. This serotype represents 28.2% (n=468) of the 1659 Salmonella isolates recovered by the Instituto Nacional de Salud (INS) Acute Diarrheal Diseases Surveillance Program from 1997 to 2004. Previously, little was known about the molecular attributes of these strains and commonality of genetic subtypes among S. Typhimurium isolated from humans in Colombia. OBJECTIVE: The purpose of this study was to characterize S. Typhimurium isolates circulating in Colombia using pulsed-field gel electrophoresis in order to establish genetic profiles and determine their potential relatedness. MATERIALS AND METHODS: 468 S. Typhimurium isolates were submitted to INS by 14 Public Health Laboratories from January 1997 to December 2004. The pulsed-field gel electrophoresis was performed using restriction enzyme Xbal according to the PulseNet standard protocol (CDC, Atlanta). Restriction pattern analysis and cluster definition were performed using Molecular Analyst Fingerprinting II software. RESULTS: 180 distinct electrophoretic patterns were obtained. Pattern COINJPX.X01.0062 was the most common (21.3% of the 473 isolates, n=101), followed by COINJPX.X01.0001 (8.4%, n=40), COINJPX.X01.0058 (3%, n=13), COINJPX.X01.0003 (2.5%, n=12), COINJPX.X01.0066 (2.3%, n=11), and COINJPX.X01.0108 (1.4%, n=6). COINJPX.X01.0001, was the most prevalent pattern among S. Typhimurium isolated in Bogotá from 1997-2002, but appeared to be replaced both in Bogotá and nationally by COINJPX.X01.0062 in 2003-2004. Cluster analysis demonstrated three distinct groups with 53% and 82% similarity indicating heterogeneity within the serotype. CONCLUSIONS: The study provides important electrophoretic pattern baseline data, which will be useful for prospective real-time comparison of profiles of future isolates. Cluster detection using this method will facilitate outbreak detection and will enhance our ability to find common sources for seemingly unrelated infections.

Acute Disease↗

PubMed2025

Construction and accuracy assessment of an efferocytosis-related prognostic model for ovarian cancer: A diagnostic accuracy study.

The study aimed to investigate the prognostic significance of efferocytosis-related genes in ovarian cancer (OC) with regard to cancer development, progression, invasion, and metastasis. OC cohorts were assembled from bioinformatics repositories. Utilizing consensus clustering analysis, distinct clusters were delineated based on the intersection of OC-related genes and efferocytosis-related genes. A prognostic signature specific to efferocytosis in OC was developed using data from The Cancer Genome Atlas, validated against the gene expression omnibus database, and subjected to independent prognostic analysis. Subsequently, a nomogram model was formulated. Moreover, investigations encompassed the immune microenvironment, immunotherapy, mutation profiling, drug sensitivity assessments, drug prediction models, and molecular docking analyses. Finally, quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were employed to ascertain the mRNA expression levels of key genes. Five key genes, FCGBP, BTN3A3, WDR91, SLC25A45, and BTNL3, were identified as significantly associated with OC. Both datasets and qRT-PCR demonstrated elevated expression levels of FCGBP and WDR91 in OC. Notably, AFLATOXIN B1 exhibited strong binding affinity to SLC25A45, ciclopirox to BTN3A3, and irinotecan to WDR91. The risk score, age, and stage were identified as independent prognostic factors, with the nomogram displaying efficacy in predicting OC patient survival. Variations in the immune cell infiltration profiles, including naive B cells, and expression levels of 6 immune checkpoint genes, such as CTLA4, were notable. High tumor mutation burden scores were associated with improved survival outcomes. Additionally, significant differences in the IC50 values of 123 anticancer drugs were observed between the 2 risk groups. This findings of this study highlight the efficacy of the efferocytosis-associated risk model in predicting the survival outcomes of OC patients, thus providing a novel reference for prognostic prediction in OC patients.

Humans↗

PubMed1987

Cluster significance analysis contrasted with three other quantitative structure-activity relationship methods.

Cluster significance analysis (CSA), a new statistical method to analyze structure-activity relationships in graphically displayed data, is contrasted with linear discriminant analysis, SIMCA, and the method of "relative odds". The data sets evaluated are as follows: antibacterial lasalocid derivatives, antimalarial naphthoquinones, and carcinogenic polycyclic aromatic hydrocarbons. CSA gives results comparable to these other methods, involves fewer assumptions, can be more reliable, and in general is easier to understand.

Antimalarials↗

PubMed1991

Data analysis of the Second International Workshop on Small Cell Lung Cancer Antigens.

Methods of data collection for the 2nd Small Cell Lung Cancer Workshop are described, and data reliability is reviewed. The method of cluster analysis of the workshop antibodies is described and discussed. Of the 27,111 results submitted 20,705 were judged to be reliable for analysis and 13,802 of these came from immunohistology experiments. Data derived from immunocytochemistry experiments were somewhat less reproducible than flow cytometry, immunohistology and ELISA experiments. The cluster analysis was developed from methods employed in the leucocyte antigens workshops. Several checks on the methods of cluster analysis and the transformation of data did not substantially alter the final groupings. The workshop confirms that, although there are some methodological difficulties, the cluster analysis can successfully be applied to data derived largely from immunohistology, and thus has applicability to other tumour types.

Antibodies, Monoclonal↗

PubMed2002

mRNA expression profiles for the response of human tumor cell lines to the antimalarial drugs artesunate, arteether, and artemether.

The antimalarial artemisinin derivatives artesunate (ART), arteether (ARE), and artemether (ARM) reveal remarkable antineoplastic activity. In the present investigation, we identified mRNA expression profiles associated with the response of tumor cells to ART, ARE, and ARM. We performed correlation and hierarchical cluster analyses of inhibition concentration 50% (IC(50)) values and basal mRNA expression levels of 464 genes deposited in the database of the National Cancer Institute, USA. Correlating IC(50) values of ART, ARE, and ARM and of 16 established antineoplastic drugs revealed that the artemisinin derivatives could not be assigned with a known class of drugs with defined mode(s) of action. The basal mRNA expression of 208 out of 464 genes (45%) correlated significantly with IC(50) values of at least one artemisinin derivative. These genes were from different classes (drug resistance genes, DNA damage and repair genes, apoptosis-regulating genes, proliferation-associated genes, oncogenes, tumor suppressor genes and cytokines). We identified two different gene clusters by hierarchical cluster analysis. One cluster contained predominately genes significantly correlated to all three artemisinin derivatives. This overlapping set of genes points to common molecular mechanisms of tumor inhibition by all three drugs in which genes affecting cellular proliferation may play an important role. The second cluster contained genes differentially associated with the response of artemisinin derivatives to cancer cells. The number of correlating drug resistance genes in this cluster increased in the order ART<ARE<ARM and was paralleled by increasing IC(50) values of the three drugs in the same order. The higher activity of ART in comparison to ARE and ARM may, thus, be explained by a lower number of drug resistance genes affecting ARTs action. The present analysis is a starting point for the generation of hypotheses on candidate genes and for a more detailed dissection of the functional role of individual genes for the activity of artemisinin derivatives in tumor cells.

Antimalarials↗

PubMed1986

Affinities between contemporary and skeletal Jewish and non-Jewish groups based on tooth morphology.

Samples from five Jewish and six non-Jewish populations were compared in terms of the frequencies of 19 dental morphological variables. All but one of the samples came from Europe, North Africa, or the Middle East. Nine were from contemporary populations, and two were skeletal. Of the skeletal groups, one was Jewish, excavated on Mount Zion, Jerusalem, and dated at around 3,000 years old; and the other non-Jewish, excavated on the east coast of Australia, and dated at between 1,000 and 200 years old. Assessment of affinity between the different groups was based on smallest space analysis and cluster analysis. The results demonstrated relative proximity of the Jewish groups (with one exception), despite the fact that they came from a wide geographical area. In particular, the sample from Mount Zion showed greater affinity with three of the four living Jewish populations than with most non-Jewish groups. The skeletal Australian sample formed a cluster of its own, distinct from all the other groups. For six of the groups, the relationships based on tooth morphology showed good correspondence with known relationships based on single locus polymorphisms. The similarity of the Jewish groups to each other in terms of both tooth morphology and single locus polymorphisms was of special interest, since differences in other morphological and anthropometric characteristics, thought to be the result of selection, are known to exist between the Jewish populations.

Africa, Northern↗

PubMed2002

Soybean germplasm pools in Asia revealed by nuclear SSRs.

Soybean was domesticated in East Asia, where various kinds of landraces have been established as a result of adaptation to different environments and the diversification of food cultures. Asia is thus an important germplasm pool of soybean. In order to evaluate the genetic structure of the Asian soybean population, we analyzed allelic profiles at 20 simple-sequence repeat (SSR) loci of 131 accessions introduced from 14 Asian countries. The SSR loci produced an average of 11.9 alleles and a mean gene diversity of 0.782 in the accessions tested. Quantification theory III analysis and cluster analysis with the UPGMA method clearly separated the Japanese from the Chinese accessions, suggesting that the Japanese and Chinese populations formed different germplasm pools. The Korean accessions were involved in both germplasm pools, whereas most of the accessions from southeast and south/central Asia were derived from the Chinese pool. Relatively high genetic diversity and the absence of region-specific clusters in the southeast and south/central Asian populations suggest that soybean in these areas has been introduced repeatedly and independently from the diverse Chinese germplasm pool. The present study indicates that the two germplasm pools can be used as exotic genetic resources to enlarge the genetic bases of the respective Asian soybean populations.

Alleles↗