• Korean Journal of Ichthyology
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• v.3 no.1
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• pp.36-41
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• 1991

The karyotype of the Niwaella multifasciata, endemic species to the Nakdong River in Korea, is reported for the first time. The sample species, Niwaella multifasciata collected from the Milyang River and the Nam River which are tributaries of the Nakdong River, has a diploid complement of 50 chromosomes composed of 10 metacentric, 28 submetacentric, 12 subtelocentric chromosomes, and 88 arm numbers. The arm number of Niwaella multifasciata was larger than any other species of Cobitidae. Sexual dimophism and intraspecific polymophism of the chromosomes were not observed in this study.

• Genomics & Informatics
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• v.13 no.4
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• pp.102-111
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• 2015

The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia.

• Journal of Interdisciplinary Genomics
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• v.4 no.2
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• pp.24-30
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• 2022

Klinefelter's syndrome (KS) is a syndrome with extra X chromosome(s), in XY individuals, characterized by gynecomastia, small testes, and infertility. Additional X chromosomes can be present as variable karyotypic forms, including mosaicism (47,XXY/46,XY). The reported prevalence of KS ranges from one in 500 to one in 1,000 live males, but is probably underestimated. The classic phenotype is small, firm testes and infertility resulting from seminiferous tubule dysgenesis and androgen deficiency. The spectrum of KS includes tall stature with relatively long legs and arm span, decreased body hair, learning disabilities, behavioral problems, poor motor skills, and other important medical issues, such as metabolic syndrome, diabetes, autoimmune diseases, cardiovascular disease, certain neoplasia. The increased risk of certain medical problems in KS can be attributed to a direct effect of the extra X chromosome, the combined action of multiple genomic and epigenetic factors, or the hormonal imbalances. Typically, chromosome analysis is not ordered for adult patients with general medical conditions, except for suspected cases of hematologic and lymphoid disorders. Even though it was found during work-up for certain disorders in adult patient, most physicians do not suspect KS or consider its impact. Therefore, understanding the pathophysiology and variable manifestation in KS is necessary, and discussions with multidisciplinary teams will help to diagnose and treat males with KS.

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.35-41
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• 1989

An examination of the karyotypes, DNA values and nuclear sizes of three scups was undertaken as part of the study of cytogenetical evolution of order Perciformes. The chromosome number 2n=48 was the same in all three species but the numbers of chromosome arm were not identical. The distribution of genome size and nuclear volumes among species was continuous ranging from 1.287 pg and $20.78\;{\mu}m^3$ for Pagrus major down to 1.237 pg and $20.56\;{\mu}m^3$ for Acanthopagrus schlegeli. Above results indicate the possible role of pericentric inversions in the karyotypic evolution of these species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.257-264
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• 1986

The Chromosomes of five cobitid fishes, Cobitis taenia taenia, C. taenia lutheri, C. taenia striata, C. longicorpus and C. koreensis were studied. The karyotypic studies were based on the observations from the flame-drying preparations. The results obtained such as the number of somatic chromosomes, the type of chromosomes according to the centromeric loci and the number of chromosomal arm(AN) were as follows: C. longicorpus, 2n=50, 12m-8sm-30a, AN=70; C. koreensis, 2n=50, 10m-12sm-28a, AN=72; C. taenia taenia, 2n=48, 14m-4sm-30a, AN=66: C. taenia lutheri, 2n=50, 10m-6sm-34a, AN=66; and C. taenia striata, 2n=50, 10m-6sm-34a, AN=66. Peculiarly, in the case of C. taenia lutheri the chromosome number of somatic diploid was found to be 48-51, however, the number of chromosomal arm was 66, irrespective of the difference in the numbers of each somatic genome. It was confirmed there exists the Robertsonian event, one of the chromosomal polymorphism in C.t. lutheri. It was remarked taxonomically that the karyotype of C. taenia taenia of Korea having 48 diploid chromosomes was not identical with that of Europe and Japan with 50 chromosomes. Based on the karyotype analysis the Korean cobitid fishes can be classified roughly into three species groups according to arm numbers and diploid numbers; 1) C. taenia taenia, C. taenia lutheri, C. taenia striata 2) C. koreensis, C. longicor pus, C. rotundicaudata and 3) C. granoei.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.147-157
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• 1992

The fragile X syndrome, which is considered to be synonymous with the Martin-Bell syndrome, is a relatively common form of X-linked mental retardation. The syndrome seems to occure in many different ethnic groups and its prevalence among mentally retarded males has been estimated to be in the order of 2 to 6%. The karyotypic hallmark of the syndrome is made up with a pronounced constriction near each tip of the long arm of the X chromosome(fragile site), shown in vitro only under conditions in which thymidylate production is blocked(lowered folate levels). Special culture media are needed to demonstrate this constriction site. Major clinical features associated with the syndrome include macroorchidism, large or prominent ears, significant emotional and behavioral dysfunctions such as hyperactivity, self-injury, lack of eye contact and social interaction, schizophrenia, autism, etc., and speech and language dysfunctions ranging from nonverbal to verbal speech with moderate to severe expressive language delays. Some have minor clinical features in common such as an increase in birth weight high forehead, prognathism, increased head circumference in infancy and childhood which did not persist into adult life. The recent research findings have shown that the fragile X syndrome is associated with infantile autism. Many patients with the fragile X syndrome fulfill the diagnostic criteria for infantile autism. Therefore it is recommendable that any patient with developmental delays and autism or autistic manifestations should have a chromosomal analysis, including fragile X examination. In the present review, historical aspects, incidence, and clinical features are presented. Recent anecdotal reports of the association with autism and the clinical improvement following high dose folic acid treatment will be discussed.