Displaying publications 21 - 40 of 163 in total

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  1. Yong RY, Gan LS, Chang YM, Yap EP
    Hum Genet, 2007 Nov;122(3-4):237-49.
    PMID: 17588179
    Amelogenin paralogs on Chromosome X (AMELX) and Y (AMELY) are commonly used sexing markers. Interstitial deletion of Yp involving the AMELY locus has previously been reported. The combined frequency of the AMELY null allele in Singapore and Malaysia populations is 2.7%, 0.6% in Indian and Malay ethnic groups respectively. It is absent among 541 Chinese screened. The null allele in this study belongs to 3 Y haplogroups; J2e1 (85.7%), F* (9.5%) and D* (4.8%). Low and high-resolution STS mapping, followed by sequence analysis of breakpoint junction confirmed a large deletion of 3 to 3.7-Mb located at the Yp11.2 region. Both breakpoints were located in TSPY repeat arrays, suggesting a non-allelic homologous recombination (NAHR) mechanism of deletion. All regional null samples shared identical breakpoint sequences according to their haplogroup affiliation, providing molecular evidence of a common ancestry origin for each haplogroup, and at least 3 independent deletion events recurred in history. The estimated ages based on Y-SNP and STR analysis were approximately 13.5 +/- 3.1 kyears and approximately 0.9 +/- 0.9 kyears for the J2e1 and F* mutations, respectively. A novel polymorphism G > A at Y-GATA-H4 locus in complete linkage disequilibrium with J2e1 null mutations is a more recent event. This work re-emphasizes the need to include other sexing markers for gender determination in certain regional populations. The frequency difference among global populations suggests it constitutes another structural variation locus of human chromosome Y. The breakpoint sequences provide further information to a better understanding of the NAHR mechanism and DNA rearrangements due to higher order genomic architecture.
    Matched MeSH terms: Chromosome Mapping
  2. Ho CL, Kwan YY, Choi MC, Tee SS, Ng WH, Lim KA, et al.
    BMC Genomics, 2007;8:381.
    PMID: 17953740
    Oil palm is the second largest source of edible oil which contributes to approximately 20% of the world's production of oils and fats. In order to understand the molecular biology involved in in vitro propagation, flowering, efficient utilization of nitrogen sources and root diseases, we have initiated an expressed sequence tag (EST) analysis on oil palm.
    Matched MeSH terms: Chromosome Mapping
  3. 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: Chromosome Mapping*
  4. Teo YY, Sim X, Ong RT, Tan AK, Chen J, Tantoso E, et al.
    Genome Res, 2009 Nov;19(11):2154-62.
    PMID: 19700652 DOI: 10.1101/gr.095000.109
    The Singapore Genome Variation Project (SGVP) provides a publicly available resource of 1.6 million single nucleotide polymorphisms (SNPs) genotyped in 268 individuals from the Chinese, Malay, and Indian population groups in Southeast Asia. This online database catalogs information and summaries on genotype and phased haplotype data, including allele frequencies, assessment of linkage disequilibrium (LD), and recombination rates in a format similar to the International HapMap Project. Here, we introduce this resource and describe the analysis of human genomic variation upon agglomerating data from the HapMap and the Human Genome Diversity Project, providing useful insights into the population structure of the three major population groups in Asia. In addition, this resource also surveyed across the genome for variation in regional patterns of LD between the HapMap and SGVP populations, and for signatures of positive natural selection using two well-established metrics: iHS and XP-EHH. The raw and processed genetic data, together with all population genetic summaries, are publicly available for download and browsing through a web browser modeled with the Generic Genome Browser.
    Matched MeSH terms: Chromosome Mapping
  5. Tam SM, Samipak S, Britt A, Chetelat RT
    Genetica, 2009 Dec;137(3):341-54.
    PMID: 19690966 DOI: 10.1007/s10709-009-9398-3
    DNA mismatch repair proteins play an essential role in maintaining genomic integrity during replication and genetic recombination. We successfully isolated a full length MSH2 and partial MSH7 cDNAs from tomato, based on sequence similarity between MutS and plant MSH homologues. Semi-quantitative RT-PCR reveals higher levels of mRNA expression of both genes in young leaves and floral buds. Genetic mapping placed MSH2 and MSH7 on chromosomes 6 and 7, respectively, and indicates that these genes exist as single copies in the tomato genome. Analysis of protein sequences and phylogeny of the plant MSH gene family show that these proteins are evolutionarily conserved, and follow the classical model of asymmetric protein evolution. Genetic manipulation of the expression of these MSH genes in tomato will provide a potentially useful tool for modifying genetic recombination and hybrid fertility between wide crosses.
    Matched MeSH terms: Chromosome Mapping
  6. Singh R, Tan SG, Panandam JM, Rahman RA, Ooi LC, Low ET, et al.
    BMC Plant Biol, 2009;9:114.
    PMID: 19706196 DOI: 10.1186/1471-2229-9-114
    Marker Assisted Selection (MAS) is well suited to a perennial crop like oil palm, in which the economic products are not produced until several years after planting. The use of DNA markers for selection in such crops can greatly reduce the number of breeding cycles needed. With the use of DNA markers, informed decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, which are satisfactory for agricultural production, and which should be culled. The trait associated with oil quality, measured in terms of its fatty acid composition, is an important agronomic trait that can eventually be tracked using molecular markers. This will speed up the production of new and improved oil palm planting materials.
    Matched MeSH terms: Chromosome Mapping*
  7. Ku CS, Pawitan Y, Sim X, Ong RT, Seielstad M, Lee EJ, et al.
    Hum Mutat, 2010 Jul;31(7):851-7.
    PMID: 20506136 DOI: 10.1002/humu.21287
    Research on the role of copy number variations (CNVs) in the genetic risk of diseases in Asian populations has been hampered by a relative lack of reference CNV maps for Asian populations outside the East Asians. In this article, we report the population characteristics of CNVs in Chinese, Malay, and Asian Indian populations in Singapore. Using the Illumina Human 1M Beadchip array, we identify 1,174 CNV loci in these populations that corroborated with findings when the same samples were typed on the Affymetrix 6.0 platform. We identify 441 novel loci not previously reported in the Database of Genomic Variations (DGV). We observe a considerable number of loci that span all three populations and were previously unreported, as well as population-specific loci that are quite common in the respective populations. From this we observe the distribution of CNVs in the Asian Indian population to be considerably different from the Chinese and Malay populations. About half of the deletion loci and three-quarters of duplication loci overlap UCSC genes. Tens of loci show population differentiation and overlap with genes previously known to be associated with genetic risk of diseases. One of these loci is the CYP2A6 deletion, previously linked to reduced susceptibility to lung cancer.
    Matched MeSH terms: Chromosome Mapping
  8. Natasya Naili MN, Hasnita CH, Shamim AK, Hasnan J, Fauziah MI, Narazah MY, et al.
    Cancer Genet. Cytogenet., 2010 Dec;203(2):309-12.
    PMID: 21156250 DOI: 10.1016/j.cancergencyto.2010.07.136
    Nasopharyngeal carcinoma (NPC) is one of the most common cancers in Malaysia, mainly occurring among the Chinese population. To detect common genetic alterations in NPC, we screened seven cases of NPC using the comparative genomic hybridization (CGH) technique. Before proceeding to the CGH technique, the tumors were first confirmed to consist of 75% tumor cells or more. In brief, the technique consists of binding tumor DNA with normal DNA and human Cot-1 DNA, which is then hybridized to normal metaphase spreads. The slides were then counterstained with 4,6 diamino-2-phenylindole (DAPI II) for detection. Analyses were performed using CGH software (Cytovision). We found genetic alterations in all seven NPC samples. The common chromosomal gains (57%, four cases) were found on chromosome arms 1q, 4p, 5, 7q, 11, 14p, 15q, 18p, and 21p, and common chromosomal losses (43%, three cases) were found on chromosome arm 16p. Our results showed chromosomal alterations in all seven NPC cases in the Malaysian population. This result provides the platform for further investigations to locate tumor suppressor genes and oncogenes at specific chromosomal regions in Malaysian NPC patients.
    Matched MeSH terms: Chromosome Mapping
  9. Seng TY, Mohamed Saad SH, Chin CW, Ting NC, Harminder Singh RS, Qamaruz Zaman F, et al.
    PLoS One, 2011;6(11):e26593.
    PMID: 22069457 DOI: 10.1371/journal.pone.0026593
    Enroute to mapping QTLs for yield components in oil palm, we constructed the linkage map of a FELDA high yielding oil palm (Elaeis guineensis), hybrid cross. The parents of the mapping population are a Deli dura and a pisifera of Yangambi origin. The cross out-yielded the average by 8-21% in four trials all of which yielded comparably to the best current commercial planting materials. The higher yield derived from a higher fruit oil content. SSR markers in the public domain - from CIRAD and MPOB, as well as some developed in FELDA - were used for the mapping, augmented by locally-designed AFLP markers. The female parent linkage map comprised 317 marker loci and the male parent map 331 loci, both in 16 linkage groups each. The number of markers per group ranged from 8-47 in the former and 12-40 in the latter. The integrated map was 2,247.5 cM long and included 479 markers and 168 anchor points. The number of markers per linkage group was 15-57, the average being 29, and the average map density 4.7 cM. The linkage groups ranged in length from 77.5 cM to 223.7 cM, with an average of 137 cM. The map is currently being validated against a closely related population and also being expanded to include yield related QTLs.
    Matched MeSH terms: Chromosome Mapping*
  10. Alexeev D, Kostrjukova E, Aliper A, Popenko A, Bazaleev N, Tyakht A, et al.
    J Proteome Res, 2012 Jan 1;11(1):224-36.
    PMID: 22129229 DOI: 10.1021/pr2008626
    To date, no genome of any of the species from the genus Spiroplasma has been completely sequenced. Long repetitive sequences similar to mobile units present a major obstacle for current genome sequencing technologies. Here, we report the assembly of the Spiroplasma melliferum KC3 genome into 4 contigs, followed by proteogenomic annotation and metabolic reconstruction based on the discovery of 521 expressed proteins and comprehensive metabolomic profiling. A systems approach allowed us to elucidate putative pathogenicity mechanisms and to discover major virulence factors, such as Chitinase utilization enzymes and toxins never before reported for insect pathogenic spiroplasmas.
    Matched MeSH terms: Chromosome Mapping
  11. Amiruddin N, Lee XW, Blake DP, Suzuki Y, Tay YL, Lim LS, et al.
    BMC Genomics, 2012 Jan 13;13:21.
    PMID: 22244352 DOI: 10.1186/1471-2164-13-21
    BACKGROUND: Eimeria tenella is an apicomplexan parasite that causes coccidiosis in the domestic fowl. Infection with this parasite is diagnosed frequently in intensively reared poultry and its control is usually accorded a high priority, especially in chickens raised for meat. Prophylactic chemotherapy has been the primary method used for the control of coccidiosis. However, drug efficacy can be compromised by drug-resistant parasites and the lack of new drugs highlights demands for alternative control strategies including vaccination. In the long term, sustainable control of coccidiosis will most likely be achieved through integrated drug and vaccination programmes. Characterisation of the E. tenella transcriptome may provide a better understanding of the biology of the parasite and aid in the development of a more effective control for coccidiosis.

    RESULTS: More than 15,000 partial sequences were generated from the 5' and 3' ends of clones randomly selected from an E. tenella second generation merozoite full-length cDNA library. Clustering of these sequences produced 1,529 unique transcripts (UTs). Based on the transcript assembly and subsequently primer walking, 433 full-length cDNA sequences were successfully generated. These sequences varied in length, ranging from 441 bp to 3,083 bp, with an average size of 1,647 bp. Simple sequence repeat (SSR) analysis identified CAG as the most abundant trinucleotide motif, while codon usage analysis revealed that the ten most infrequently used codons in E. tenella are UAU, UGU, GUA, CAU, AUA, CGA, UUA, CUA, CGU and AGU. Subsequent analysis of the E. tenella complete coding sequences identified 25 putative secretory and 60 putative surface proteins, all of which are now rational candidates for development as recombinant vaccines or drug targets in the effort to control avian coccidiosis.

    CONCLUSIONS: This paper describes the generation and characterisation of full-length cDNA sequences from E. tenella second generation merozoites and provides new insights into the E. tenella transcriptome. The data generated will be useful for the development and validation of diagnostic and control strategies for coccidiosis and will be of value in annotation of the E. tenella genome sequence.

    Matched MeSH terms: Chromosome Mapping
  12. Kashiani P, Saleh G, Panandam JM, Abdullah NA, Selamat A
    Genet Mol Biol, 2012 Jul;35(3):614-21.
    PMID: 23055801 DOI: 10.1590/S1415-47572012000400012
    A study of genetic variation among 10 pairs of chromosomes extracted from 13 tropical sweet corn inbred lines, using 99 microsatellite markers, revealed a wide range of genetic diversity. Allelic richness and the number of effective alleles per chromosome ranged from 2.78 to 4.33 and 1.96 to 3.47, respectively, with respective mean values of 3.62 and 2.73. According to the Shannon's information index (I) and Nei's gene diversity coefficient (Nei), Chromosome 10 was the most informative chromosome (I = 1.311 and Nei = 0.703), while Chromosome 2 possessed the least (I = 0.762 and Nei = 0.456). Based on linkage disequilibrium (LD) measurements for loci less than 50 cM apart on the same chromosome, all loci on Chromosomes 1, 6 and 7 were in equilibrium. Even so, there was a high proportion of genetic variation in Chromosomes 4, 5, 8, 9 and 10, thereby revealing their appropriateness for use in the genetic diversity investigations among tropical sweet corn lines. Chromosome 4, with the highest number of loci in linkage disequilibrium, was considered the best for marker-phenotype association and QTL mapping, followed by Chromosomes 5, 8, 9 and 10.
    Matched MeSH terms: Chromosome Mapping
  13. Ngeow YF, Wong YL, Lokanathan N, Wong GJ, Ong CS, Ng KP, et al.
    J Bacteriol, 2012 Sep;194(17):4786.
    PMID: 22887681 DOI: 10.1128/JB.01104-12
    We report the draft genome sequence of a clinical isolate, strain M115, identified as Mycobacterium massiliense, a member of the newly created taxon of Mycobacterium abscessus subspecies bolletii comb. nov.
    Matched MeSH terms: Chromosome Mapping
  14. Choo SW, Wong YL, Tan JL, Ong CS, Wong GJ, Ng KP, et al.
    J Bacteriol, 2012 Sep;194(17):4778.
    PMID: 22887675 DOI: 10.1128/JB.01043-12
    Mycobacterium massiliense has recently been proposed as a member of Mycobacterium abscessus subsp. bolletii comb. nov. Strain M154, a clinical isolate from the bronchoalveolar lavage fluid of a Malaysian patient presenting with lower respiratory tract infection, was subjected to shotgun DNA sequencing with the Illumina sequencing technology to obtain whole-genome sequence data for comparison with other genetically related strains within the M. abscessus species complex.
    Matched MeSH terms: Chromosome Mapping
  15. Gan HM, Chew TH, Tay YL, Lye SF, Yahya A
    J Bacteriol, 2012 Sep;194(17):4759-60.
    PMID: 22887664 DOI: 10.1128/JB.00990-12
    Hydrogenophaga sp. strain PBC is an effective degrader of 4-aminobenzenesulfonate isolated from textile wastewater. Here we present the assembly and annotation of its genome, which may provide further insights into its metabolic potential. This is the first announcement of the draft genome sequence of a strain from the genus Hydrogenophaga.
    Matched MeSH terms: Chromosome Mapping
  16. Rahim HA, Bhuiyan MA, Lim LS, Sabu KK, Saad A, Azhar M, et al.
    Genet. Mol. Res., 2012;11(3):3277-89.
    PMID: 23079822 DOI: 10.4238/2012.September.12.11
    Advanced backcross families derived from Oryza sativa cv MR219/O. rufipogon IRGC105491 were utilized for identification of quantitative trait loci (QTL) for blast resistance using simple sequence repeat markers. Two hundred and sixty-one BC(2)F(3) families were used to construct a linkage map, using 87 markers, which covered 2375.2 cM of 12 rice chromosomes, with a mean density of 27.3 cM. The families were evaluated in a greenhouse for resistance to blast disease caused by pathotypes P7.2 and P5.0 of Magnaporthe oryzae. Five QTLs (qBL5.1, qBL5.2, qBL6.1, qBL8.1, and qBL10.1) for pathotype P5.0 and four QTLs (qBL5.3, qBL5.4, qBL7.1, and qBL8.2) for pathotype P7.2 were identified using the BC(2)F(3) families. Another linkage map was also constructed based on 31 BC(2)F(5) families, using 63 SSR markers, which covered 474.9 cM of 9 rice chromosomes, with a mean density of 8.01 cM. Five suggestive QTLs (qBL11.2, qBL11.3, qBL12.1, qBL12.2, qBL12.3) and one putative QTL (qBL2.1) were identified for pathotype P7.2. Also, seven suggestive QTLs (qBL1.1, qBL2.2, qBL4.1, qBL4.2, qBL5.3, qBL8.3, and qBL11.1) were detected for pathotype P5.0. We conclude that there is a non-race-specific resistance spectrum of O. rufipogon against M. oryzae pathotypes.
    Matched MeSH terms: Chromosome Mapping
  17. Wong MM, Cannon CH, Wickneswari R
    BMC Genomics, 2012;13:726.
    PMID: 23265623 DOI: 10.1186/1471-2164-13-726
    Next Generation Sequencing has provided comprehensive, affordable and high-throughput DNA sequences for Single Nucleotide Polymorphism (SNP) discovery in Acacia auriculiformis and Acacia mangium. Like other non-model species, SNP detection and genotyping in Acacia are challenging due to lack of genome sequences. The main objective of this study is to develop the first high-throughput SNP genotyping assay for linkage map construction of A. auriculiformis x A. mangium hybrids.
    Matched MeSH terms: Chromosome Mapping
  18. Sahilah Abu Mutalib, Wan Sakeenah Wan Nazari, Safiyyah Shahimi, Norhayati Yaakob, Norrakiah Abdullah Sani, Aminah Abdullah, et al.
    Sains Malaysiana, 2012;41:199-204.
    A method of PCR-restriction fragment length polymorphism (RFLP) has been utilized to differentiate the mitochondrial genes of pork and wild boar meat (Sus scrofa). The amplification PCR products of 359 bp and 531 bp were successfully amplified from the cyt b gene of these two meats. The amplification product of pork and wild boar using mt-12S rRNA gene successfully produced a single band with molecular size of 456 bp. Three restriction endonucleases (AluI, HindIII and BsaJI) were used to restrict the amplification products of the mitochondrial genes. The restriction enzymes of AluI and BsaJI were identified as potential restriction endonucleases to differentiate those meats. HindIII enzyme was unable to restrict the PCR product of both meats. The genetic differences within the cyt b gene among the two meats were successfully confirmed by PCR-RFLP analysis.
    Matched MeSH terms: Chromosome Mapping
  19. Ashkani S, Rafii MY, Rahim HA, Latif MA
    Mol Biol Rep, 2013 Mar;40(3):2503-15.
    PMID: 23203411 DOI: 10.1007/s11033-012-2331-3
    Rice blast is one of the major fungal diseases that badly reduce rice production in Asia including Malaysia. There is not much information on identification of QTLs as well as linked markers and their association with blast resistance within local rice cultivars. In order to understanding of the genetic control of blast in the F3 families from indica rice cross Pongsu seribu2/Mahsuri, an analysis of quantitative trait loci against one of the highly virulent Malaysian rice blast isolate Magnaporthe oryzae, P5.0 was carried out. Result indicated that partial resistance to this pathotype observed in the present study was controlled by multiple loci or different QTLs. In QTL analysis in F3 progeny fifteen QTLs on chromosomes 1, 2, 3, 5, 6, 11 and 12 for resistance to blast nursery tests was identified. Three of detected QTLs (qRBr-6.1, qRBr-11.4, and qRBr-12.1) had significant threshold (LOD >3) and approved by both IM and CIM methods. Twelve suggestive QTLs, qRBr-1.2, qRBr-2.1, qRBr-4.1, qRBr-5.1, qRBr-6.2, qRBr-6.3, qRBr-8.1, qRBr-10.1, qRBr-10.2, qRBr-11.1, qRBr-11.2 and qRBr-11.3) with Logarithmic of Odds (LOD) <3.0 or LRS <15) were distributed on chromosomes 1, 2, 4, 5, 6, 8, 10, and 11. Most of the QTLs detected using single isolate had the resistant alleles from Pongsu seribu 2 which involved in the resistance in the greenhouse. We found that QTLs detected for deferent traits for the using isolate were frequently located in similar genomic regions. Inheritance study showed among F3 lines resistance segregated in the expected ratio of 15: 1 for resistant to susceptible. The average score for blast resistance measured in the green house was 3.15, 1.98 and 29.95 % for three traits, BLD, BLT and % DLA, respectively.
    Matched MeSH terms: Chromosome Mapping*
  20. Wong CM, Tam HK, Ng WM, Boo SY, González M
    Plasmid, 2013 Mar;69(2):186-93.
    PMID: 23266397 DOI: 10.1016/j.plasmid.2012.12.002
    A cryptic plasmid, pMWHK1 recovered from an Antarctic bacterium Pedobacter cryoconitis BG5 was sequenced and characterised. The plasmid is a circular 6206bp molecule with eight putative open reading frames designated as orf1, orf2, orf3, orf4, orf5, orf6, orf7 and orf8. All the putative open reading frames of pMWHK1 are found to be actively transcribed. Proteins encoded by orf2 and orf4 are predicted to be responsible for the mobilization and replication of the plasmid respectively. orf4 shares 55% and 61% identities with the theta-type Rep proteins from two strains of Riemerella anatipestifer. This suggests that pMWHK1 could be a member of the theta-type replicating plasmid. The origin of replication is located within the AT-rich region upstream of orf4. orf5 and orf6 encode bacterial toxin-antitoxin proteins predicted to maintain plasmid stability. orf3 encodes an entry exclusion protein that is hypothetically involved in reducing the frequency of DNA transfer through conjugation. orf1, orf7 and orf8 encode proteins with unknown functions. Plasmid, pMWHK1 is stably maintained in P. cryoconitis BG5 at 20°C.
    Matched MeSH terms: Physical Chromosome Mapping
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