Displaying publications 101 - 120 of 275 in total

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  1. Haplotype diversity of 16 Y-chromosomal STRs in three main ethnic populations (Malays, Chinese and Indians) in Malaysia
    Chang YM, Perumal R, Keat PY, Kuehn DL
    Forensic Sci Int, 2007 Mar 22;167(1):70-6.
    PMID: 16457976
    We have analyzed 16 Y-STR loci (DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385a/b, DYS393, DYS391, DYS439, DYS635 or Y-GATA C4, DYS392, Y-GATA H4, DYS437, DYS438 and DYS448) from the non-recombining region of the human Y-chromosome in 980 male individuals from three main ethnic populations in Malaysia (Malay, Chinese, Indian) using the AmpFlSTR((R)) Y-filertrade mark (Applied Biosystems, Foster City, CA). The observed 17-loci haplotypes and the individual allele frequencies for each locus were estimated, whilst the locus diversity, haplotype diversity and discrimination capacity were calculated in the three ethnic populations. Analysis of molecular variance indicated that 88.7% of the haplotypic variation is found within population and 11.3% is between populations (fixation index F(ST)=0.113, p=0.000). This study has revealed Y-chromosomes with null alleles at several Y-loci, namely DYS458, DYS392, DYS389I, DYS389II, DYS439, DYS448 and Y-GATA H4; and several occurrences of duplications at the highly polymorphic DYS385 loci. Some of these deleted loci were in regions of the Y(q) arm that have been implicated in the occurrence of male infertility.
    Matched MeSH terms: Chromosomes, Human, Y*
  2. Fulltext Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome
    Machiela MJ, Zhou W, Karlins E, Sampson JN, Freedman ND, Yang Q, et al.
    Nat Commun, 2016 06 13;7:11843.
    PMID: 27291797 DOI: 10.1038/ncomms11843
    To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.
    Matched MeSH terms: Chromosomes, Human, X/genetics*
  3. Fulltext Tests of conspecificity for allopatric vectors: Simulium nodosum and Simulium shirakii (Diptera: Simuliidae) in Asia
    Low VL, Adler PH, Sofian-Azirun M, Srisuka W, Saeung A, Huang YT, et al.
    Parasit Vectors, 2015 May 29;8:297.
    PMID: 26022092 DOI: 10.1186/s13071-015-0911-5
    BACKGROUND: Allopatric populations present challenges for biologists working with vectors. We suggest that conspecificity can be concluded in these cases when data from four character sets-chromosomal, ecological, molecular, and morphological-express variation no greater between the allopatric populations than between corresponding sympatric populations. We use this approach to test the conspecificity of Simulium nodosum Puri on the mainland of Southeast Asia and Simulium shirakii Kono & Takahasi in Taiwan. The validity of these two putative species has long been disputed given that they are morphologically indistinguishable.

    FINDINGS: The mitochondria-encoded cytochrome c oxidase subunit I (COI), 12S rRNA, and 16S rRNA genes and the nuclear-encoded 28S rRNA gene support the conspecific status of S. nodosum from Myanmar, Thailand, and Vietnam and S. shirakii from Taiwan; 0 to 0.19 % genetic differences between the two taxa suggest intraspecific polymorphism. The banding patterns of the polytene chromosomes of the insular Taiwanese population of S. shirakii and mainland populations of S. nodosum are congruent. The overlapping ranges of habitat characteristics and hosts of S. nodosum and S. shirakii corroborate the chromosomal, molecular, and morphological data.

    CONCLUSIONS: Four independent sources of evidence (chromosomes, DNA, ecology, and morphology) support the conspecificity of S. nodosum and S. shirakii. We, therefore, synonymize S. shirakii with S. nodosum. This study provides a guide for applying the procedure of testing conspecificity to other sets of allopatric vectors.

    Matched MeSH terms: Polytene Chromosomes/genetics*
  4. Pulsed-field gel electrophoresis of chromosomal DNA of methicillin-resistant Staphylococcus aureus associated with nosocomial infections
    Hanifah YA, Hiramatsu K
    Malays J Pathol, 1994 Dec;16(2):151-6.
    PMID: 9053564
    Methicillin-resistant Staphylococcus aureus (MRSA) infection has been endemic in the University Hospital, Kuala Lumpur since the late 1970s. Fifty isolates of MRSA obtained from clinical specimens of patients with nosocomial infections associated with this organism have been studied by pulsed-field gel electrophoresis (PFGE) of its chromosomal DNA fragments to discrimate between strains and to identify the predominant strain. Twenty-one chromosomal patterns were observed which could be further grouped into nine types. The predominant strain was Type 9-b (40% of isolates) found mainly in the Orthopaedic and Surgical Units. Outbreak strains found in the Special Care Nursery were of Type 1, entirely different from those of the surgical ward S2, which were of Type 9-b. Type 8 strains were found mainly at one end of the hospital building where the maternity, paediatric and orthopaedic units were situated. Genomic DNA fingerprinting by PFGE is recommended as a useful and effective tool for the purpose of epidemiological studies of MSRA infections, particularly for nosocomial infections.
    Matched MeSH terms: Chromosomes, Bacterial*
  5. Genome size variation among recent human isolates of Salmonella typhi
    Thong KL, Puthucheary SD, Pang T
    Res. Microbiol., 1997 Mar-Apr;148(3):229-35.
    PMID: 9765803
    We performed genome size estimation of 17 recent human isolates of Salmonella typhi from geographically diverse regions using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with restriction endonucleases XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3') and SpeI (5'-ACTAGT-3'), and summation of the sizes of restriction fragments obtained. All 17 isolates had circular chromosomes, and genome sizes differed by as much as 959 kb, ranging from 3,964 to 4,923 kb (mean genome size = 4,528 kb). The data obtained confirm the usefulness of PFGE in studies of bacterial genome size and are in agreement with recent results indicating considerable genetic diversity and genomic plasticity of S. typhi. The variation in genome sizes noted may be relevant to the observed biological properties of this important human pathogen, including its virulence.
    Matched MeSH terms: Chromosomes, Bacterial/genetics
  6. Paternal lineage affinity of the Malay subethnic and Orang Asli populations in Peninsular Malaysia
    SharifahNany RahayuKarmilla S, Aedrianee AR, Nur Haslindawaty AR, Nur Azeelah A, Panneerchelvam S, Norazmi MN, et al.
    Int J Legal Med, 2018 Jul;132(4):1087-1090.
    PMID: 29052042 DOI: 10.1007/s00414-017-1697-0
    Peninsular Malaysia is populated by the Malays, Chinese, Indians, and Orang Asli. We have analyzed 17 Y-STRs loci for 243 randomly unrelated individuals, which include 153 Malays (7 Acheh, 13 Champa, 11 Rawa, 9 Kedah, 23 Minang, 15 Bugis, 43 Kelantan, 14 Jawa, and 18 Bugis) and 90 Orang Asli [54 Semang (16 Kensiu, 13 Lanoh, 25 Bateq); 30 Senoi (21 Semai, 9 Che Wong); and 6 Proto-Malay (6 Orang Kanaq)] from selected settlements in Peninsular Malaysia using the AmpFlSTR Yfiler™ kit (Applied Biosystems™). The overall haplotype diversity is 0.9966, i.e., 0.9984 for the Malays and 0.9793 for the Orang Asli. A total of 158 haplotypes (65.02%) were individually unique. The p value and pairwise Rst analysis was calculated to show the genetic structure of the samples with other world populations (from YHRD website). Based on the Y-STR data, Champa, Acheh, Kedah, Minang, and Kelantan are clustered together. Lanoh and Kensiu (Semang) are very closely related, suggesting similar paternal ancestry. Jawa Malays and Indonesian Java, plus the Bugis Malays and Australian Aborigines shared high degree of paternal lineage affinity. This study presents data for very precious relict groups, who are the earliest inhabitants of Peninsular Malaysia.
    Matched MeSH terms: Chromosomes, Human, Y*
  7. Fulltext Y Chromosome Sequences Reveal a Short Beringian Standstill, Rapid Expansion, and early Population structure of Native American Founders
    Pinotti T, Bergström A, Geppert M, Bawn M, Ohasi D, Shi W, et al.
    Curr Biol, 2019 01 07;29(1):149-157.e3.
    PMID: 30581024 DOI: 10.1016/j.cub.2018.11.029
    The Americas were the last inhabitable continents to be occupied by humans, with a growing multidisciplinary consensus for entry 15-25 thousand years ago (kya) from northeast Asia via the former Beringia land bridge [1-4]. Autosomal DNA analyses have dated the separation of Native American ancestors from the Asian gene pool to 23 kya or later [5, 6] and mtDNA analyses to ∼25 kya [7], followed by isolation ("Beringian Standstill" [8, 9]) for 2.4-9 ky and then a rapid expansion throughout the Americas. Here, we present a calibrated sequence-based analysis of 222 Native American and relevant Eurasian Y chromosomes (24 new) from haplogroups Q and C [10], with four major conclusions. First, we identify three to four independent lineages as autochthonous and likely founders: the major Q-M3 and rarer Q-CTS1780 present throughout the Americas, the very rare C3-MPB373 in South America, and possibly the C3-P39/Z30536 in North America. Second, from the divergence times and Eurasian/American distribution of lineages, we estimate a Beringian Standstill duration of 2.7 ky or 4.6 ky, according to alternative models, and entry south of the ice sheet after 19.5 kya. Third, we describe the star-like expansion of Q-M848 (within Q-M3) starting at 15 kya [11] in the Americas, followed by establishment of substantial spatial structure in South America by 12 kya. Fourth, the deep branches of the Q-CTS1780 lineage present at low frequencies throughout the Americas today [12] may reflect a separate out-of-Beringia dispersal after the melting of the glaciers at the end of the Pleistocene.
    Matched MeSH terms: Chromosomes, Human, Y/genetics*
  8. Population data of 23 Y chromosome STR loci for the five major human subpopulations of Ghana
    Kofi AE, Hakim HM, Khan HO, Ismail SA, Ghansah A, David AA, et al.
    Int J Legal Med, 2020 Jul;134(4):1313-1315.
    PMID: 31154498 DOI: 10.1007/s00414-019-02099-w
    In this study, 268 samples for unrelated males belonging to the five major human subpopulation groups in Ghana (Akan, Ewe, Mole-Dagbon, Ga-Dangme and Guang) were genetically characterised for 23 Y chromosome short tandem repeat (STR) loci using the Powerplex® Y23 STR kit. A total of 263 complete haplotypes were recorded of which 258 were unique. The haplotype diversity, discriminating capacity and match probability for the pooled population data were 0.9998, 0.9627 and 0.0039, respectively. The pairwise genetic distance (RST) for the Ghanaian datasets and other reference populations deposited in the Y-STR Haplotype Reference Database (YHRD) were estimated and mapped using multidimensional scaling (MDS) plot. The Guang and Ewe were significantly different from the Akan, Mole-Dagbon and Ga-Dangme. However, the five Ghanaian datasets were all plotted close together with other African populations in the MDS data mapping.
    Matched MeSH terms: Chromosomes, Human, Y*
  9. Population data for 23 Y chromosome STR loci using the Powerplex® Y23 STR kit for the Kedayan population in Malaysia
    Hakim HM, Khan HO, Ismail SA, Lalung J, Kofi AE, Nelson BR, et al.
    Int J Legal Med, 2020 Jul;134(4):1335-1337.
    PMID: 31897667 DOI: 10.1007/s00414-019-02237-4
    Genetic polymorphisms at 23 Y chromosome short tandem repeat (STRs) loci included in the Powerplex® Y23 PCR kit were successfully scored in 128 unrelated Kedayan individuals living in Sabah, East Malaysia. Complete haplotypes were recorded for all individuals and included 92 different types with 72 being unique to single male subjects. Three important forensic statistics were calculated from these data; haplotype diversity = 0.993, discriminating capacity = 0.719, and match probability = 0.015. The Kedayan appear to be most closely related to Malays and Filipinos in a multidimensional scaling plot and are separated from other mainland Asia populations including Thais and Hakka Han. These new data for Kedayan have been deposited in the YHRD database (accession number: YA004621). Our statistical analyses showed the reliability of Y-STR loci for geographically extended use in forensic casework and for studying human population history.
    Matched MeSH terms: Chromosomes, Human, Y*
  10. Genomewide selection in oil palm: increasing selection gain per unit time and cost with small populations
    Wong CK, Bernardo R
    Theor Appl Genet, 2008 Apr;116(6):815-24.
    PMID: 18219476 DOI: 10.1007/s00122-008-0715-5
    Oil palm (Elaeis guineensis Jacq.) requires 19 years per cycle of phenotypic selection. The use of molecular markers may reduce the generation interval and the cost of oil-palm breeding. Our objectives were to compare, by simulation, the response to phenotypic selection, marker-assisted recurrent selection (MARS), and genomewide selection with small population sizes in oil palm, and assess the efficiency of each method in terms of years and cost per unit gain. Markers significantly associated with the trait were used to calculate the marker scores in MARS, whereas all markers were used (without significance tests) to calculate the marker scores in genomewide selection. Responses to phenotypic selection and genomewide selection were consistently greater than the response to MARS. With population sizes of N = 50 or 70, responses to genomewide selection were 4-25% larger than the corresponding responses to phenotypic selection, depending on the heritability and number of quantitative trait loci. Cost per unit gain was 26-57% lower with genomewide selection than with phenotypic selection when markers cost US $1.50 per data point, and 35-65% lower when markers cost $0.15 per data point. With population sizes of N = 50 or 70, time per unit gain was 11-23 years with genomewide selection and 14-25 years with phenotypic selection. We conclude that for a realistic yet relatively small population size of N = 50 in oil palm, genomewide selection is superior to MARS and phenotypic selection in terms of gain per unit cost and time. Our results should be generally applicable to other tree species that are characterized by long generation intervals, high costs of maintaining breeding plantations, and small population sizes in selection programs.
    Matched MeSH terms: Chromosomes, Plant*
  11. Characterization of a Saccharum spontaneum with a basic chromosome number of x = 10 provides new insights on genome evolution in genus Saccharum
    Meng Z, Han J, Lin Y, Zhao Y, Lin Q, Ma X, et al.
    Theor Appl Genet, 2020 Jan;133(1):187-199.
    PMID: 31587087 DOI: 10.1007/s00122-019-03450-w
    KEY MESSAGE: A novel tetraploid S. spontaneum with basic chromosome x = 10 was discovered, providing us insights in the origin and evolution in Saccharum species. Sugarcane (Saccharum spp., Poaceae) is a leading crop for sugar production providing 80% of the world's sugar. However, the genetic and genomic complexities of this crop such as its high polyploidy level and highly variable chromosome numbers have significantly hindered the studies in deciphering the genomic structure and evolution of sugarcane. Here, we developed the first set of oligonucleotide (oligo)-based probes based on the S. spontaneum genome (x = 8), which can be used to simultaneously distinguish each of the 64 chromosomes of octaploid S. spontaneum SES208 (2n = 8x = 64) through fluorescence in situ hybridization (FISH). By comparative FISH assay, we confirmed the chromosomal rearrangements of S. spontaneum (x = 8) and S. officinarum (2n = 8x = 80), the main contributors of modern sugarcane cultivars. In addition, we examined a S. spontaneum accession, Np-X, with 2n = 40 chromosomes, and we found that it was a tetraploid with the unusual basic chromosome number of x = 10. Assays at the cytological and DNA levels demonstrated its close relationship with S. spontaneum with basic chromosome number x = 8 (the most common accessions in S. spontaneum), confirming its S. spontaneum identity. Population genetic structure and phylogenetic relationship analyses between Np-X and 64 S. spontaneum accessions revealed that Np-X belongs to the ancient Pan-Malaysia group, indicating a close relationship to S. spontaneum with basic chromosome number of x = 8. This finding of a tetraploid S. spontaneum with basic chromosome number of x = 10 suggested a parallel evolution path of genomes and polyploid series in S. spontaneum with different basic chromosome numbers.
    Matched MeSH terms: Chromosomes, Plant/genetics*
  12. A rare case of metastatic lung carcinoma with t(15;19)(q13;p13.1) and trisomy 12
    Tay Za K, Bee PC, Shanmugam H
    Pathology, 2020 Feb;52(2):273-276.
    PMID: 31883672 DOI: 10.1016/j.pathol.2019.10.013
    Matched MeSH terms: Chromosomes, Human, Pair 12/genetics
  13. Fulltext Development of High-Density SNP Markers and Their Application in Evaluating Genetic Diversity and Population Structure in Elaeis guineensis
    Xia W, Luo T, Zhang W, Mason AS, Huang D, Huang X, et al.
    Front Plant Sci, 2019;10:130.
    PMID: 30809240 DOI: 10.3389/fpls.2019.00130
    High-density single nucleotide polymorphisms (SNPs) are used as highly favored makers to analyze genetic diversity and population structure, to construct high-density genetic maps and provide genotypes for genome-wide association analysis. In order to develop genome-wide SNP markers in oil palm (Elaeis guineensis), single locus amplified fragment sequencing (SLAF-seq) technology was performed in a diversity panel of 200 oil palm individuals and 1,261,501 SNPs were identified with minor allele frequency > 0.05 and integrity > 1. Among them, only 17.81% can be mapped within the genic region and the remaining was located into the intergenic region. A positive correlation was detected between the distribution of SNP markers and retrotransposons [transposable elements (TEs)]. Population structure analysis showed that the 200 individuals of oil palm can be divided into five subgroups based on cross-validation errors. However, the subpopulations divided for the 200 oil palm individuals based on the SNP markers were not accurately related to their geographical origins and 80 oil palm individuals from Malaysia showed highest genetic diversity. In addition, the physical distance of linkage disequilibrium (LD) decay in the analyzed oil palm population was 14.516 kb when r2 = 0.1. The LD decay distances for different chromosomes varied from 3.324 (chromosome 15) to 19.983 kb (chromosome 7). Our research provides genome-wide SNPs for future targeted breeding in palm oil.
    Matched MeSH terms: Chromosomes, Human, Pair 15; Chromosomes, Human, Pair 7
  14. Genotoxic and cytotoxic effects in the bone marrow of rats exposed to a low dose of paraquat via the dermal route
    D'Souza UJ, Zain A, Raju S
    Mutat Res, 2005 Mar 7;581(1-2):187-90.
    PMID: 15725618
    The genotoxic effect of the herbicide paraquat was studied in rat bone-marrow by means of the micronucleus assay. Paraquat at dose levels of 6, 15 and 30 mg/kg body weight was given to rats in a single application via the dermal route. Marrow was collected at 24, 48 and 72 h after the application. The micronucleus assay was done as recommended by standard procedures. Paraquat gave rise to an increase in the number of micronuclei in a dose-dependent manner. The number of micronucleated polychromatic erythrocytes showed a maximum at 48 h and the toxicity was further prolonged, as there was no complete recovery at 72 h. These findings suggest a genotoxic effect of paraquat even after exposure via dermal application.
    Matched MeSH terms: Chromosomes/drug effects
  15. Clinical stage of chronic granulocytic leukaemia and BCR breakpoint location in South-East Asian patients
    Dyck JA, Bosco JJ
    Br J Haematol, 1989 May;72(1):64-7.
    PMID: 2736243
    Forty-six Malaysian patients with chronic granulocytic leukaemia were found to be rearranged in the breakpoint cluster region (BCR) of chromosome 22, molecular evidence of Philadelphia chromosome (t9.22) translocation. Through the use of a 1.2 kb 3' BCR probe and two restriction enzyme digests, patients' breakpoints could be localized either to 5' or 3' regions of the BCR. Breakpoint site localization at the time of DNA sampling did not show any positive statistical association to clinical status defined as chronic phase, chronic phase with less than 6 months to blast crisis, accelerated phase and blast crisis. This was in contrast to earlier reports which indicated that patients with breakpoint at 3' site were at a higher biologic risk for entering blast crisis.
    Matched MeSH terms: Chromosomes, Human, Pair 22*
  16. Meiotic drive does not cause condition-dependent reduction of the sexual ornament in stalk-eyed flies
    Finnegan SR, Mondani M, Fowler K, Pomiankowski A
    J Evol Biol, 2021 05;34(5):736-745.
    PMID: 33559198 DOI: 10.1111/jeb.13770
    Meiotic drive systems are associated with low-frequency chromosomal inversions. These are expected to accumulate deleterious mutations due to reduced recombination and low effective population size. We test this prediction using the 'sex-ratio' (SR) meiotic drive system of the Malaysian stalk-eyed fly Teleopsis dalmanni. SR is associated with a large inversion (or inversions) on the X chromosome. In particular, we study eyespan in males carrying the SR chromosome, as this trait is a highly exaggerated, sexually dimorphic trait, known to have heightened condition-dependent expression. Larvae were raised in low and high larval food stress environments. SR males showed reduced eyespan under the low and high stress treatments, but there was no evidence of a condition-dependent decrease in eyespan under high stress. Similar but more complex patterns were observed for female eyespan, with evidence of additivity under low stress and heterosis under high stress. These results do not support the hypothesis that reduced sexual ornament size in meiotic drive males is due to a condition-dependent response to the putative increase in mutation load. Instead, reduced eyespan likely reflects compensatory resource allocation to different traits in response to drive-mediated destruction of sperm.
    Matched MeSH terms: Chromosomes, Insect*
  17. Population data and genetic characteristics of 12 X-STR loci using the Investigator® Argus X-12 Quality Sensor kit for the Kedayan population of Borneo in Malaysia
    Hakim HM, Khan HO, Ismail SA, Lalung J, Kofi AE, Aziz MY, et al.
    Int J Legal Med, 2021 Jul;135(4):1433-1435.
    PMID: 33782746 DOI: 10.1007/s00414-021-02577-0
    DNA profiling of X-chromosomal short tandem repeats (X-STR) has exceptional value in criminal investigations, especially for complex kinship and incest cases. In this study, Investigator® Argus X-12 Quality Sensor (QS) kits were successfully used to characterize 12 X-STR loci in 199 unrelated healthy Kedayan individuals living in Sabah and Sarawak, Malaysia. The LG1 haplogroup (DXS8378 - DXS10135 - DXS10148) has the largest HD (0.9799) as compared with all other closely linked haplotype groups examined (LG2; DXS7132-DXS10074-DXS10079, LG3; DXS10103-DXS10101-HPRTB and LG4; DXS10134-DXS7423-DXS10146). Data from statistical analysis showed that high combined of PDM, PDF, MEC_Krüger, MEC_Kishida, MEC_Desmarais, and MEC_Desmarais_duo values (0.999999994405922, 0.99999999999999, 0.999990463834938, 0.999999975914808, 0.999999975985006, and 0.999996491927194, respectively) in the Kedayan. In a two-dimensional scaling (MDS) plot and dendrogram constructed using allele frequencies at the 12 X-STR loci, Kedayan appear to be most closely related to their other Austronesian populations including the Malays and Filipinos as compared with other reference population groups. Findings from the present study thus demonstrate high genetic variability across the 12 tested X-STR loci and can be used for population studies and forensic applications.
    Matched MeSH terms: Chromosomes, Human, X*
  18. Fulltext Ageing Effects, Generation Means, and Path Coefficient Analyses on High Kernel Elongation in Mahsuri Mutan and Basmati 370 Rice Populations
    Ab Halim AAB, Rafii MY, Osman MB, Oladosu Y, Chukwu SC
    Biomed Res Int, 2021;2021:8350136.
    PMID: 34095311 DOI: 10.1155/2021/8350136
    High kernel elongation (HKE) is one of the high-quality characteristics in rice. The objectives of this study were to determine the effects of ageing treatments, gene actions, and inheritance pattern of kernel elongation on cooking quality in two populations of rice and determine the path of influence and contribution of other traits to kernel elongation in rice. Two rice populations derived from crosses between MR219 × Mahsuri Mutan and MR219 × Basmati 370 were used. The breeding materials included two F1 progenies from the two populations, and their respective parents were grown in four different batches at a week interval to synchronize the flowering between the female and male plants. Scaling tests and generation means analysis were carried out to determine ageing effects and estimate additive-dominance gene action and epistasis. The estimation of gene interaction was based on quantitative traits. Path coefficient analysis was done using SAS software version 9.4 to determine the path of influence (direct or indirect) of six quantitative traits on HKE. Results obtained showed that nonallelic gene interaction was observed in all traits. The results before ageing and after ageing showed significant differences in all traits, while the gene interaction changed after ageing. The HKE value improved after ageing, suggesting that ageing is an external factor that could influence gene expression. The epistasis effect for HKE obtained from the cross Mahsuri Mutan × MR219 showed duplicate epistasis while that obtained from a cross between Basmati 370 × MR219 showed complimentary epistasis. Besides, the heritability of HKE was higher in Basmati 370 × MR219 compared to that obtained in Mahsuri Mutan × MR219. The path analysis showed that the cooked grain length and length-width ratio positively significantly affected HKE. It was concluded that ageing treatment is an external factor that could improve the expression of HKE. The findings from this study would be useful to breeders in the selection and development of new specialty (HKE) rice varieties.
    Matched MeSH terms: Chromosomes, Plant/genetics
  19. FISHing for 1p19q codel in oligodendroglioma
    Kong PL, Cheah PL, Mun KS, Chiew SF, Lau TP, Koh CC, et al.
    Malays J Pathol, 2020 Dec;42(3):369-376.
    PMID: 33361717
    Together with isocitrate dehydrogenase (IDH) mutation, co-deletion of 1p19q (1p19q codel) is a prerequisite for diagnosis of oligodendroglioma, making it imperative that histopathology laboratories introduce testing for 1p19q codel. To date there is still no consensus reference range and cut-offs that confirm deletion of 1p or 19q. We embarked on determining our reference range in 11 formalinfixed, paraffin-embedded non-neoplastic brain tissue using fluorescence in situ hybridisation (FISH) with the Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit (Abbott Molecular Inc., USA). At same time we attempted to validate our methodology in 13 histologically-confirmed IDH-mutant oligodendrogliomas. For 1p, percentage cells with deletion (range=8-23%; mean±SD = 15.73±5.50%) and target: control (1p36:1q25) ratio (range = 0.89-0.96; mean±SD = 0.92±0.03) in non-neoplastic brain, differed significantly (p<0.000) from oligodendroglioma (percentage cells with deletion: range = 49-100%; mean±SD = 82.46±15.21%; target:control ratio range:0.50-0.76; mean±SD = 0.59±0.08). For 19q, percentage cells with deletion (range = 7-20%; mean±SD = 12.00±3.49%) and target:control (19q13/19p13) ratio (range:0.90-0.97; mean±SD = 0.94±0.02) in non-neoplastic brain also differed significantly from oligodendroglioma (percentage cells with deletion: range = 45-100%; mean±SD = 82.62±18.13%; target:control ratio range:0.50-0.78; mean±SD = 0.59±0.09). Using recommended calculation method, for diagnosis of 1p deletion, percentage of cells showing deletion should be >32-33% and/or target:control ratio <0.83. For 19q, percentage of cells showing deletion should be >22% and target:control ratio <0.88. Using these cut-offs all 13 oligodendroglioma demonstrated 1p19q codel.
    Matched MeSH terms: Chromosomes, Human, Pair 1/genetics*
  20. Fulltext Fine-Scale Mapping at 9p22.2 Identifies Candidate Causal Variants That Modify Ovarian Cancer Risk in BRCA1 and BRCA2 Mutation Carriers
    Vigorito E, Kuchenbaecker KB, Beesley J, Adlard J, Agnarsson BA, Andrulis IL, et al.
    PLoS One, 2016;11(7):e0158801.
    PMID: 27463617 DOI: 10.1371/journal.pone.0158801
    Population-based genome wide association studies have identified a locus at 9p22.2 associated with ovarian cancer risk, which also modifies ovarian cancer risk in BRCA1 and BRCA2 mutation carriers. We conducted fine-scale mapping at 9p22.2 to identify potential causal variants in BRCA1 and BRCA2 mutation carriers. Genotype data were available for 15,252 (2,462 ovarian cancer cases) BRCA1 and 8,211 (631 ovarian cancer cases) BRCA2 mutation carriers. Following genotype imputation, ovarian cancer associations were assessed for 4,873 and 5,020 SNPs in BRCA1 and BRCA 2 mutation carriers respectively, within a retrospective cohort analytical framework. In BRCA1 mutation carriers one set of eight correlated candidate causal variants for ovarian cancer risk modification was identified (top SNP rs10124837, HR: 0.73, 95%CI: 0.68 to 0.79, p-value 2× 10-16). These variants were located up to 20 kb upstream of BNC2. In BRCA2 mutation carriers one region, up to 45 kb upstream of BNC2, and containing 100 correlated SNPs was identified as candidate causal (top SNP rs62543585, HR: 0.69, 95%CI: 0.59 to 0.80, p-value 1.0 × 10-6). The candidate causal in BRCA1 mutation carriers did not include the strongest associated variant at this locus in the general population. In sum, we identified a set of candidate causal variants in a region that encompasses the BNC2 transcription start site. The ovarian cancer association at 9p22.2 may be mediated by different variants in BRCA1 mutation carriers and in the general population. Thus, potentially different mechanisms may underlie ovarian cancer risk for mutation carriers and the general population.
    Matched MeSH terms: Chromosomes, Human, Pair 9*
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