Displaying publications 1 - 20 of 77 in total

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  1. Volleth M, Greilhuber J, Heller KG, Müller S, Yong HS, Loidl J
    Chromosoma, 2023 Nov;132(4):269-288.
    PMID: 37322170 DOI: 10.1007/s00412-023-00802-w
    The average genome size (GS) of bats, which are the only mammals capable of powered flight, is approximately 18% smaller than that of closely related mammalian orders. The low nuclear DNA content of Chiroptera is comparable to that of birds, which are also characterized by a high metabolic rate. Only a few chiropteran taxa possess notable amounts of constitutive heterochromatin. Here, we studied the karyotypes of two non-related vesper bat species with unusually high amounts of constitutive heterochromatin: Hesperoptenus doriae and Philetor brachypterus. Conventional staining methods and whole-chromosome painting with probes derived from Myotis myotis (2n = 44), showing a karyotype close to that of the presumed ancestor of Vespertilionidae, revealed Robertsonian fusions as the main type of rearrangement leading to the exceptionally reduced diploid chromosome number of 2n = 26 in both species. Moreover, both karyotypes are characterized by large blocks of pericentromeric heterochromatin composed of CMA-positive and DA-DAPI-positive segments. In H. doriae, the heterochromatin accumulation has resulted in a genome size of 3.22 pg (1C), which is 40% greater than the mean genome size for the family. For P. brachypterus, a genome size of 2.94 pg was determined, representing an increase of about 28%. Most notably, in H. doriae, the presence of additional constitutive heterochromatin correlates with an extended mitotic cell cycle duration in vitro. A reduction in diploid chromosome number to 30 or lower is discussed as a possible cause of the accumulation of pericentromeric heterochromatin in Vespertilionidae.
    Matched MeSH terms: Karyotyping
  2. Yang CF, Hsu CY, Hsiao LT, Chen SW, Chuang SS
    Malays J Pathol, 2023 Dec;45(3):405-416.
    PMID: 38155382
    BACKGROUND: Myelodysplastic syndromes (MDS) are a group of clonal haematopoietic stem cell disorders characterised by ineffective haematopoiesis and cytopenia. Studies have reported differences in MDS between Asian and Western countries, but data from Taiwan are scarce.

    MATERIALS AND METHODS: In this study we analysed the clinical and pathological features of 32 Taiwanese MDS patients with del(5q) (ie, del(5q) alone [Group A, n = 11], del(5q) with one additional cytogenetic abnormality other than monosomy 7 or del(7q) [Group B, del(5q)+1; n = 6], and del(5q) with ≥2 additional cytogenetic abnormalities [Group C, n = 15]).

    RESULTS: Progression-free survival (PFS) and overall survival (OS) were more favourable for Group A than for Groups B (p < 0.05) and C (p ≤ 0.001). Multivariate analysis showed that age >70 years, thrombocytopenia, and karyotype other than del(5q) alone were poor prognostic factors. Among the patients that had World Health Organization (WHO)-defined MDS with isolated del(5q), one patient (9%) had a typical marrow morphology of 5q minus syndrome with erythroid hypoplasia and four patients (36%) had hypolobated megakaryocytes. In addition, PFS and OS were significantly more favorable for the patients with del(5q) alone than for those with del(5q)+1 (p < 0.05).

    CONCLUSION: The bone marrow morphology, clinical features, and prognosis of Taiwanese MDS patients with del(5q) were different from those associated with MDS with isolated del(5q) as defined in the current WHO classification. Researchers should compare different geographic regions and racial populations to determine whether geographic and racial differences exist with respect to MDS with del(5q).

    Matched MeSH terms: Karyotyping
  3. Yong HS, Mak JW
    PMID: 3043697
    The current information on isoenzyme studies of nematode parasites was reviewed. The genetic heterogeneity as reviewed by these studies was highlighted. Application of isoenzyme studies and the role of biotechnological techniques in isoenzyme studies was discussed, and the status of cytogenetic studies on nematode parasites was presented.
    Matched MeSH terms: Karyotyping/veterinary
  4. Denzer W, Manthey U, Mahlow K, Böhme W
    Zootaxa, 2015;4039(1):129-44.
    PMID: 26624470 DOI: 10.11646/zootaxa.4039.1.5
    The generic assignment of the draconine lizard Gonocephalus robinsonii from the highlands of West-Malaysia has been uncertain since the original description. Here we present a study based on morphology, previously published karyotype data and molecular phylogenetics using 16S rRNA sequences to evaluate the systematic status of G. robinsonii. As a result we describe Malayodracon gen. nov. to accommodate the species.
    Matched MeSH terms: Karyotyping
  5. Yong HS, Dhaliwal SS, Lim BL
    Cytologia (Tokyo), 1982 Dec;47(3-4):535-8.
    PMID: 7166052
    Matched MeSH terms: Karyotyping
  6. Shaari N'AL, Jaoi-Edward M, Loo SS, Salisi MS, Yusoff R, Ab Ghani NI, et al.
    BMC Genet, 2019 03 25;20(1):37.
    PMID: 30909863 DOI: 10.1186/s12863-019-0741-0
    BACKGROUND: In Malaysia, the domestic water buffaloes (Bubalus bubalis) are classified into the swamp and the murrah buffaloes. Identification of these buffaloes is usually made via their phenotypic appearances. This study characterizes the subspecies of water buffaloes using karyotype, molecular and phylogenetic analyses. Blood of 105 buffaloes, phenotypically identified as swamp, murrah and crossbred buffaloes were cultured, terminated and harvested using conventional karyotype protocol to determine the number of chromosomes. Then, the D-loop of mitochondrial DNA of 10 swamp, 6 crossbred and 4 murrah buffaloes which were identified earlier by karyotyping were used to construct a phylogenetic tree was constructed.

    RESULTS: Karyotypic analysis confirmed that all 93 animals phenotypically identified as swamp buffaloes with 48 chromosomes, all 7 as crossbreds with 49 chromosomes, and all 5 as murrah buffaloes with 50 chromosomes. The D-loop of mitochondrial DNA analysis showed that 10 haplotypes were observed with haplotype diversity of 0.8000 ± 0.089. Sequence characterization revealed 72 variables sites in which 67 were parsimony informative sites with sequence diversity of 0.01906. The swamp and murrah buffaloes clearly formed 2 different clades in the phylogenetic tree, indicating clear maternal divergence from each other. The crossbreds were grouped within the swamp buffalo clade, indicating the dominant maternal swamp buffalo gene in the crossbreds.

    CONCLUSION: Thus, the karyotyping could be used to differentiate the water buffaloes while genotypic analysis could be used to characterize the water buffaloes and their crossbreds.

    Matched MeSH terms: Karyotyping
  7. Ten SK, Chin YM, Noor PJ, Hassan K
    Singapore Med J, 1990 Aug;31(4):355-9.
    PMID: 2255934
    Cytogenetic investigations were carried out on 117 women with primary amenorrhea who had been referred to our Genetics Laboratory by clinicians throughout Malaysia, after exclusion of other causes of the disorder. Thirty-six cases (31%) showed numerical or structural abnormalities of the sex chromosomes. These can be broadly classified into 4 main types, namely, presence of a Y chromosome (14%), X-chromosome aneuploidies (8%), structural anomalies of the X-chromosome (7%) and lastly, presence of a marker chromosome (2%). Mosaics constituted 17% of the abnormalities observed, always in association with a 45,X cell line. There was no observable correlation between the phenotype of the patients and their respective abnormal karyotypes. The aetiological role of sex chromosomal abnormalities in these amenorrheic women is discussed.
    Matched MeSH terms: Karyotyping
  8. Rogatcheva MB, Borodin PM, Oda SI, Searle JB
    Genome, 1997 Feb;40(1):18-24.
    PMID: 9061910
    A high-resolution G-banding technique was used to identify five metacentrics that characterize Suncus murinus from Sri Lanka. These metacentrics were shown to be the product of Robertsonian fusion of acrocentric chromosomes identical to those in the standard karyotype defined by M.B. Rogatcheva et al. Two of the metacentrics in the Sri Lankan shrews (Rb(10.12) and Rb(14.15)) were the same as those reported by C.H. Sam et al. in Malayan populations of S. murinus. This finding provides strong support for the suggestion of T.H. Yosida that metacentric-carrying shrews colonized Malaya from Sri Lanka and hybridized with individuals of standard karyotype, generating the Robertsonian polymorphism now observed. In addition to the Robertsonian variation in S. murinus, we have used our high resolution technique (G- and C-banding) to characterize variants on chromosome 7, the X chromosome, and the Y chromosome.
    Matched MeSH terms: Karyotyping
  9. Harisah M, Azmi TI, Hilmi M, Vidyadaran MK, Bongso TA, Nava ZM, et al.
    Genome, 1989 Dec;32(6):999-1002.
    PMID: 2628159
    Chromosome analysis on different breed types of water buffaloes (Bubalus bubalis) was undertaken to identify their karyotypes and to determine the pattern of chromosome segregation in crossbred water buffaloes. Altogether, 75 purebred and 198 crossbred buffaloes including 118 from Malaysia and 80 from the Philippines, were analyzed in this study. The diploid chromosome number of the swamp buffalo from both countries was 48 and that of the river buffalo was 50, while all F1 hybrids exhibited 49 chromosomes. The F2 hybrids consisted of three different karyotype categories (2n = 48, 2n = 49, and 2n = 50), whereas the backcrosses included two different karyotype categories each, with 2n = 48 and 2n = 49 in the three quarters swamp types and 2n = 49 and 2n = 50 in the three quarters river types. Chi-square tests on pooled data from Malaysia and the Philippines indicated that the distribution of different karyotype categories of F2 animals did not deviate significantly from the 1:2:1 ratio expected if only balanced gametes with 24 and 25 chromosomes were produced by the F1 hybrids. In the three quarters swamp and three quarters river types, the respective karyotypic categories were in ratios approximating 1:1. The distribution of chromosome categories among the F2 hybrids and backcrosses suggests that only genetically balanced gametes of the F1 hybrids are capable of producing viable F2 and backcross generations.
    Matched MeSH terms: Karyotyping
  10. Chin YM, Hassan K
    Med J Malaysia, 1984 Jun;39(2):103-11.
    PMID: 6595495
    The common chromosome abnormalities that are encountered in the various types of leukemia are discussed here. Chromosome abnormalities in leukemia are non-random and certain chromosomal changes are now becoming recognised as being rather specific for certain leukemia types.
    Matched MeSH terms: Karyotyping
  11. Yip MY, Yong HS, Dhaliwal SS
    Med J Malaysia, 1978 Jun;32(4):316-20.
    PMID: 732631
    Matched MeSH terms: Karyotyping
  12. Hoi-Sen Y
    Nature, 1971 Aug 13;232(5311):484-5.
    PMID: 4937212
    Matched MeSH terms: Karyotyping
  13. Boon WH
    Med J Malaya, 1969 Jun;23(4):272-81.
    PMID: 4242175
    Matched MeSH terms: Karyotyping
  14. Kutty MK, Dutt AK, Lopez G, Ramanathan K, Pillay DR, Omar-Ahmad UD
    Med J Malaya, 1968 Sep;23(1):51-3.
    PMID: 4237557
    Matched MeSH terms: Karyotyping
  15. Cheah JS, Tan BY
    Med J Malaya, 1969 Mar;23(3):181-8.
    PMID: 4240071
    Matched MeSH terms: Karyotyping
  16. Yosida TH
    Cytogenet. Cell Genet., 1977;18(3):149-59.
    PMID: 862437
    Supernumerary chromosomes have been examined in 352 black rats, covering three geographic variants, by use of conventional and C-band staining techniques. Metacentric supernumerary chromosomes, one to three in number, were found in Malayan black rats (Rattus rattus diardii), with 2n=42, in Indian black rats (R. rattus rufescens), with 2n=38, and in Ceylonese black rats (R. rattus kandianus), with 2n=40. The supernumeraries had similar morphology and stained heavily along their entire length by C-band staining. These findings suggested that the supernumeraries had originally developed in the Asian-type black rats and then were sequentially transmitted to the Ceylonese and Oceanian-type black rats, probably in southwestern Asia. A subtelocentric supernumerary chromosome found in one Japanese black rat seemed to have developed independently from the above metacentric supernumeraries.
    Matched MeSH terms: Karyotyping
  17. Liu Meng, Ding Gongtao, Roziah Bt. Kambol
    Science Letters, 2016;10(1):8-10.
    MyJurnal
    Cytogenetics studies in domestic animal are
    gaining importance because of their genetics and implication in
    breeding programmes. The present study describes the
    chromosome number and karyotypic characteristics of Ganjia
    sheep and comparison between males and females breeds. We
    adopt the method of cultivating somatic cells, and analyzed the
    chromosome karyotype of the Ganjia sheep. The result
    indicates the diploid chromosome of the Gangia sheep is 2n=54,
    in which 26 pairs of autosomes and a pair of sex chromosome
    were observed. Result indicates all autosomes are tip silk. The X
    chromosome was acrocentric and largest except the first three
    pairs that were metacentric. The Y chromosome was the
    smallest, biarmed and probably metacentric chromosome.
    Matched MeSH terms: Karyotyping
  18. Oliver JH, Tanaka K, Sawada M
    Chromosoma, 1974 May 10;45(4):445-56.
    PMID: 4837734
    Matched MeSH terms: Karyotyping
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