Publications by authors named "Geoffrey Keith Chambers"

14 Publications

  • Page 1 of 1

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.

Int J Legal Med 2021 Jul 30;135(4):1433-1435. Epub 2021 Mar 30.

Forensic Science Programme, School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150, Kubang Kerian, Kelantan, Malaysia.

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 PD, PD, MEC_, MEC_, MEC_, and MEC_ 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.
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http://dx.doi.org/10.1007/s00414-021-02577-0DOI Listing
July 2021

The Prevalence of Transfusion-transmitted Infections among Blood Donors in Hospital Universiti Sains Malaysia.

Oman Med J 2020 Nov 20;35(6):e189. Epub 2020 Oct 20.

Transfusion Medicine Unit, Hospital Universiti Sains Malaysia, Universiti Sains Malaysia, Kelantan, Malaysia.

Objectives: Blood bank centers routinely screen for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) to ensure the safety of blood supply and thus prevent the dissemination of these viruses via blood transfusion. We sought to evaluate the detection of transfusion-transmitted infection (TTI) markers using standard serological methods and nucleic acid testing (NAT) among blood donors in Hospital Universiti Sains Malaysia.

Methods: Donated blood units were assessed for the presence or absence of HBV, HCV, and HIV using two screening method: serology and NAT. Reactive blood samples were then subjected to serological confirmatory and NAT discriminatory assays.

Results: A total of 9669 donors were recruited from September 2017 to June 2018. Among these, 36 donors were reactive either for HBV, HCV, or HIV by serological testing and eight by NAT screening. However, only 10 (three for HBV and seven for HCV) donors tested positive using serological testing and five (two for HBV and three for HCV) by NAT discriminatory assays. Note that all five NAT positive donors detected in the NAT discriminatory assays were confirmed to be serologically reactive. Therefore, the prevalence of HBV, HCV, and HIV was 0.03%, 0.1%, and 0.0%, respectively, in our donor pool.

Conclusions: Both serological and NAT screening and confirmatory assays should be used routinely to reduce the risk of infection transmission via the transfusion of blood and blood components.
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http://dx.doi.org/10.5001/omj.2020.86DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7577371PMC
November 2020

Autosomal STR Profiling and Databanking in Malaysia: Current Status and Future Prospects.

Genes (Basel) 2020 09 23;11(10). Epub 2020 Sep 23.

Institute of Tropical Biodiversity and Sustainable Development, Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia.

Science and technology are extensively used in criminal investigation. From the mid- to late-1980s, one of the scientific discoveries that has had a particularly remarkable impact on this field has been the use of highly variable DNA sequence regions (minisatellites) in the human genome for individual identification. The technique was initially referred to as DNA fingerprinting, but is now more widely referred to as DNA profiling. Since then, many new developments have occurred within this area of science. These include the introduction of new genetic markers (microsatellites also known as short tandem repeats/STRs), the use of the polymerase chain reaction for target amplification, the development of DNA databases (databanking), and the advancement and/or improvement of genotyping protocols and technologies. In 2019, we described the progress of DNA profiling and DNA databanking in Malaysia for the first time. This report included information on DNA analysis regulations and legislation, STR genotyping protocols, database management, and accreditation status. Here, we provide an update on the performance of our DNA databank (numbers of DNA profiles and hits) plus the technical issues associated with correctly assigning the weight of evidence for DNA profiles in an ethnically diverse population, and the potential application of rapid DNA testing in the country. A total of 116,534 DNA profiles were obtained and stored in the Forensic DNA Databank of Malaysia (FDDM) by 2019, having increased from 70,570 in 2017. The number of hits increased by more than three-fold in just two years, where 17 and 69 hits between the DNA profiles stored in the FDDM and those from crime scenes, suspects, detainees, drug users, convicts, missing persons, or volunteers were recorded in 2017 and 2019, respectively. Forensic DNA analysis and databanking are thus progressing well in Malaysia and have already contributed to many criminal investigations. However, several other issues are discussed here, including the need for STR population data for uncharacterized population groups, and pilot trials for adopting rapid DNA profiling technology. These aspects should be considered by policy makers and law enforcement agencies in order to increase the reliability and efficiency of DNA profiling in criminal cases and in kinship analysis in Malaysia.
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http://dx.doi.org/10.3390/genes11101112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597947PMC
September 2020

Dataset on 21 autosomal and two sex determining short tandem repeat loci in the Kedayan population in Borneo, Malaysia.

Data Brief 2020 Aug 21;31:105909. Epub 2020 Jun 21.

Forensic Science Programme, School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia.

This data article provides population frequencies for 21 autosomal and two sex determining short tandem repeat (STR) loci in unrelated Kedayan individuals. This article is related to the research paper entitled "Forensic parameters and ancestral fraction in the Kedayan population inferred using 21 autosomal STR loci" [1] where these same data were subjected to ancestry and forensic analyses. We have collected 200 blood samples consisting of 128 male and 72 female volunteer representatives from Kedayan people residing in various parts of Borneo. All 23 STR loci were simultaneously amplified using Globalfiler™ Express PCR and amplicons were separated using an ABI 3500xl Genetic Analyzer. The STR allele calls at each locus were called using GeneMapper ID-X Software v1.4, while several algorithms in Arlequin software version 3.5 were used to estimate Hardy-Weinberg equilibrium (HWE) and linkage disequilibrium (LD) between pairs of STR loci.
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http://dx.doi.org/10.1016/j.dib.2020.105909DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7334294PMC
August 2020

Population dataset for 21 simple tandem repeat loci in the Akan population of Ghana.

Data Brief 2020 Aug 22;31:105746. Epub 2020 May 22.

School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia.

Short tandem repeat (STR) loci are widely used as genetic marker for ancestral and forensic analyses. The latter application includes for paternity testing and DNA profiling of samples collected from scenes of crime and suspects. This survey provides the first dataset for 21 STR loci across the Akan population in Ghana by genotyping of 109 unrelated healthy individuals using Investigator 24plex kit. None of the STR loci screened deviated from Hardy-Weinberg equilibrium after applying Bonferroni correction. Overall, 224 unique alleles were observed with allele frequencies ranging from 0.005 to 0.518. The combined match probability, combined power of exclusion and combined power discrimination were 1 in 4.07 × 10, 0.999999999 and 1, respectively. Principal coordinate analysis carried out using 21 STR allele frequency data mapped the Akans with Nigerian subpopulation groups (Hausa, Igbo and Yoruba), but separated from Thais of Thailand, Chechen of Jordan and Tijuana of Mexico.
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http://dx.doi.org/10.1016/j.dib.2020.105746DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7262416PMC
August 2020

Population data for 23 Y chromosome STR loci using the Powerplex® Y23 STR kit for the Kedayan population in Malaysia.

Int J Legal Med 2020 Jul 2;134(4):1335-1337. Epub 2020 Jan 2.

Forensic Science Programme, School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150, Kubang Kerian, Kelantan, Malaysia.

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.
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http://dx.doi.org/10.1007/s00414-019-02237-4DOI Listing
July 2020

Violent crime datasets: Incidence and patterns in Malaysia from 2006 to 2017.

Data Brief 2019 Oct 3;26:104449. Epub 2019 Sep 3.

School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150, Kubang Kerian, Kelantan, Malaysia.

This article provides violent crime data in Malaysia from 2006 to 2017. The violent crimes include murder, rape, gang robbery, robbery and voluntarily causing hurt cases. A total of 330,395 violent crime cases were reported in this 12 year period and the data were tabulated state by state for all thirteen states of Malaysia, including two states in Borneo (Sabah and Sarawak) and one federal territory (Kuala Lumpur). In general, violent crimes show a decreasing trend from 2006 to 2017 in Malaysia. However, armed gang robbery and armed robbery show a fluctuating pattern from 2008 to 2011. A similar pattern was also recorded for unarmed gang robbery from 2008 to 2010. The violent crime data deposited here are available for further analysis, e.g., for identifying risk factors such as demography, lifestyle, socio-economic status, government policies etc. which may be associated with violent crime incidence and pattern across the country.
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http://dx.doi.org/10.1016/j.dib.2019.104449DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6811922PMC
October 2019

Human neutrophil antigen frequency data for Malays, Chinese and Indians.

Transfus Apher Sci 2020 Apr 4;59(2):102651. Epub 2019 Oct 4.

School of Health Sciences, Universiti Sains Malaysia, Health Campus, Kelantan, Malaysia. Electronic address:

Background: Human neutrophil antigens (HNAs) are implicated in several clinical disorders and their allelic variations have been reported for many populations. This new study was aimed to report the genotype and alleles frequencies of HNA-1, -3, -4 and -5 loci in Malays, Chinese and Indians in Peninsular Malaysia.

Methods: A total of 222 blood samples were collected from healthy, unrelated Malay, Chinese and Indian individuals. Their HNA-1, -3 and -4 and HNA-5 loci were genotyped using polymerase chain reaction-sequence specific primer (PCR-SSP) or PCR-restriction fragment length polymorphism (RFLP) assays.

Results: All HNA loci are polymorphic, except for HNA -4. Geneotypes HNA-1a/1b, -3a/3b and -4a/4a were observed most frequently at these three loci in all three ethnic groups. In contrast, HNA-5a/5b and -5a/5a were observed as the predominant genotypes in Malays vs. Chinese and Indians, respectively. The Malays, Chinese and Indians shared HNA -3a (0.505-0.527), HNA -4a (1.000) and -5a (0.676-0.854) as the most frequent alleles. However, HNA-1a was found to be the most common in Malays (0.506) and Chinese (0.504) and HNA-1b for Indians (0.525).

Conclusion: Combined with HNA data that have been published for Malay subethnic and Orang Asli groups, this study provides the first fully comprehensive HNA dataset for populations to be found in Peninsular Malaysia. Overall, our findings provide further evidence of genetic complexity in the region. This now publicly available HNA dataset can be used as a reliable reference source for improving medical outcomes.
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http://dx.doi.org/10.1016/j.transci.2019.09.004DOI Listing
April 2020

Assessment of autosomal and male DNA extracted from casework samples using Casework Direct Kit, Custom and Maxwell 16 System DNA IQ Casework Pro Kit for autosomal-STR and Y-STR profiling.

Sci Rep 2019 10 10;9(1):14558. Epub 2019 Oct 10.

Forensic Science Programme, School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150, Kubang Kerian, Kelantan, Malaysia.

Short repetitive regions in autosomal and Y chromosomes known as short tandem repeats (STRs) are currently used for DNA profiling in crime investigations. However, DNA profiling requires a sufficient quality and quantity of DNA template, which is often not obtained from trace evidence or degraded biological samples collected at the scene of a crime. Here, we assessed autosomal and male DNA components extracted from crime scene and mock casework samples using the Casework Direct Kit, Custom and compared the results against those obtained by extraction of matching samples using well-established Maxwell 16 System DNA IQ Casework Pro Kit. The quantity and quality of extracted DNA obtained using both Casework Direct Kit, Custom and Maxwell 16 System DNA IQ Casework Pro Kit were analyzed using PowerQuant Systems followed by autosomal and Y-chromosome STR profiling using GlobalFiler Express PCR Amplification Kit and PowerPlex Y23 System, respectively. Our results showed that the Casework Direct Kit and Maxwell 16 DNA IQ Casework Pro Kit have more or less equal capacity to extract inhibitor free DNA, but that the latter produces slightly better quality and more DNA template and subsequently higher numbers of STR allele calls for autosomal and Y-STR analyses. Nonetheless, the Casework Direct Kit, Custom is the quicker and cheaper option for extraction of good, clean DNA from high content material and might best be used for extraction of reference samples. Such reference DNA samples typically come from buccal swabs or freshly drawn blood. So, in general, they can confidently be expected to have a high nucleic acid content and to be inhibitor-free.
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http://dx.doi.org/10.1038/s41598-019-51154-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6787247PMC
October 2019

Population data of 23 Y chromosome STR loci for the five major human subpopulations of Ghana.

Int J Legal Med 2020 Jul 1;134(4):1313-1315. Epub 2019 Jun 1.

School of Health Sciences, Universiti Sains Malaysia, Health Campus, 16150, Kubang Kerian, Kelantan, Malaysia.

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 (R) 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.
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http://dx.doi.org/10.1007/s00414-019-02099-wDOI Listing
July 2020

Transfusion Medicine and Molecular Genetic Methods.

Int J Prev Med 2018 16;9:45. Epub 2018 May 16.

School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kelantan, Malaysia.

Transfusion procedures are always complicated by potential genetic mismatching between donor and recipient. Compatibility is determined by several major antigens, such as the ABO and Rhesus blood groups. Matching for other blood groups (Kell, Kidd, Duffy, and MNS), human platelet antigens, and human leukocyte antigens (HLAs) also contributes toward the successful transfusion outcomes, especially in multitransfused or highly immunized patients. All these antigens of tissue identity are highly polymorphic and thus present great challenges for finding suitable donors for transfusion patients. The ABO blood group and HLA markers are also the determinants of transplant compatibility, and mismatched antigens will cause graft rejection or graft-versus-host disease. Thus, a single and comprehensive registry covering all of the significant transfusion and transplantation antigens is expected to become an important tool in providing an efficient service capable of delivering safe blood and quickly locating matching organs/stem cells. This review article is intended as an accessible guide for physicians who care for transfusion-dependent patients. In particular, it serves to introduce the new molecular screening methods together with the biology of these systems, which underlies the tests.
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http://dx.doi.org/10.4103/ijpvm.IJPVM_232_16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981227PMC
May 2018

The genetic history of Peninsular Malaysia.

Gene 2016 Jul 7;586(1):129-35. Epub 2016 Apr 7.

Forensic Science Programme, School of Health Sciences, Universiti Sains Malaysia, Health Campus, Kelantan, Malaysia. Electronic address:

This article explores the genetic history of the various sub-populations currently living in Peninsular Malaysia. This region has received multiple waves of migrants like the Orang Asli in prehistoric times and the Chinese, Indians, Europeans and Arabs during historic times. There are three highly distinct lineages that make up the Orang Asli; Semang, Senoi and Proto-Malays. The Semang, who have 'Negrito' characteristics, represent the first human settlers in Peninsular Malaysia arriving from about 50,000ya. The Senoi later migrated from Indochina and are a mix between an Asian Neolithic population and the Semang. These Asian genomes probably came in before Austroasiatic languages arrived between 5000 and 4000years ago. Semang and Senoi both now speak Austro-Asiatic languages indicative of cultural diffusion from Senoi to Semang. In contrast, the Proto-Malays who came last to the southern part of this region speak Austronesian language and are Austronesians with some Negrito admixture. It is from this group that the contemporary Malays emerged. Here we provide an overview of the best available genetic evidences (single nucleotide polymorphisms, mitochondrial DNA, Y-chromosome, blood groups, human platelet antigen, human leukocyte antigen, human neutrophil antigen and killer-cell immunoglobulin-like receptor) supporting the complex genetic history of Peninsular Malaysia. Large scale sampling and high throughput genetic screening programmes such as those using genome-wide single nucleotide polymorphism analyses have provided insights into various ancestral and admixture genetic fractions in this region. Given the now extensive admixture present in the contemporary descendants of ancient sub-populations in Peninsular Malaysia, improved reconstruction of human migration history in this region will require new evidence from ancient DNA in well-preserved skeletons. All other aspects of the highly diverse and complex genetic makeup in Peninsular Malaysia should be considered carefully for genetic mapping of disease loci and policy formation by health authorities.
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http://dx.doi.org/10.1016/j.gene.2016.04.008DOI Listing
July 2016

Molecular blood group typing in Banjar, Jawa, Mandailing and Kelantan Malays in Peninsular Malaysia.

Transfus Apher Sci 2015 Aug 16;53(1):69-73. Epub 2015 Mar 16.

Human Identification Unit, School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kelantan, Malaysia. Electronic address:

In this study we genotyped ABO, Rhesus, Kell, Kidd and Duffy blood group loci in DNA samples from 120 unrelated individuals representing four Malay subethnic groups living in Peninsular Malaysia (Banjar: n = 30, Jawa: n = 30, Mandailing: n = 30 and Kelantan: n = 30). Analyses were performed using commercial polymerase chain reaction-sequence specific primer (PCR-SSP) typing kits (BAG Health Care GmbH, Lich, Germany). Overall, the present study has successfully compiled blood group datasets for the four Malay subethnic groups and used the datasets for studying ancestry and health.
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http://dx.doi.org/10.1016/j.transci.2015.03.009DOI Listing
August 2015