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Allozyme polymorphisms and heavy metal levels in the green-lipped mussel Perna viridis (Linnaeus) collected from contaminated and uncontaminated sites in Malaysia

Yap CK, Tan SG, Ismail A, Omar H

Environ Int, 2004 Mar;30(1):39-46.
PMID: 14664863

It has been widely reported that heavy metal contamination in coastal waters can modify the allozyme profiles of marine organisms. Previous studies have recorded elevated metal concentrations in sediments and mussel tissues off Peninsular Malaysia. In the present study, horizontal starch gel electrophoresis was carried out to estimate the levels of allelic variation of the green-lipped mussel, Perna viridis, collected from one contaminated and three relatively uncontaminated sites off Peninsular Malaysia. Fourteen polymorphic loci were observed. In addition, the concentrations of cadmium, copper, lead, mercury and zinc were determined in the sediments and in the soft tissues of the mussels. Mussels from contaminated site, evidenced by high metal pollution indices (MPI) of the sediment and the mussel tissues, showed the highest percentage of polymorphic loci (78.6%), while those collected from the uncontaminated sites had lower MPI of the sediment and mussel tissue, and exhibited lower percentages of polymorphic loci (35.7-57.1%). The population from the contaminated site showed the highest excess of heterozygosity (0.289) when compared to that of the populations from the three uncontaminated sites (0.108-0.149). Allozyme frequencies at the phosphoglucomutase (PGM; E.C. 2.7.5.1) locus also differed between the contaminated and uncontaminated populations. Previous studies have shown that exposure to heavy metals can select or counter-select for particular alleles at this locus. The present results suggest that allozyme polymorphism in P. viridis is a potential biomonitoring tool for heavy metal contamination but further validation is required.

Matched MeSH terms: Gene Frequency/genetics
Inference of the Genetic Polymorphisms of CYP2D6 in Six Subtribes of the Malaysian Orang Asli from Whole-Genome Sequencing Data

Yu CY, Ang GY, Subramaniam V, Johari James R, Ahmad A, Abdul Rahman T, et al.

Genet Test Mol Biomarkers, 2017 Jul;21(7):409-415.
PMID: 28525288 DOI: 10.1089/gtmb.2016.0235

AIMS: CYP2D6 is one of the major enzymes in the cytochrome P450 monooxygenase system. It metabolizes ∼25% of prescribed drugs and hence, the genetic diversity of a CYP2D6 gene has continued to be of great interest to the medical and pharmaceutical industries. This study was designed to perform a systematic analysis of the CYP2D6 gene in six subtribes of the Malaysian Orang Asli.
METHODS: Genomic DNAs were extracted from the blood samples followed by whole-genome sequencing. The reads were aligned to the reference human genome hg19 and variants in the CYP2D6 gene were analyzed. CYP2D6*5 and duplication of CYP2D6 were analyzed using previously established methods.
RESULTS: A total of 72 single nucleotide polymorphisms were identified. CYP2D6*1, *2, *4, *5, *10,*41, and duplication of the gene were found in the Orang Asli, whereby CYP2D6*2 and *41 alleles are reported for the first time in the Malaysian population.
CONCLUSION: The findings in this study provide insights into the genetic polymorphisms of CYP2D6 in the Orang Asli of Peninsular Malaysia.

Matched MeSH terms: Gene Frequency/genetics
Nonsynonymous polymorphisms of the PDLIM5 gene association with the occurrence of both bipolar disorder and schizophrenia

Zain MA, Roffeei SN, Zainal NZ, Kanagasundram S, Mohamed Z

Psychiatr Genet, 2013 Dec;23(6):258-61.
PMID: 24064681 DOI: 10.1097/YPG.0000000000000015

Two single nucleotide polymorphisms of PDLIM5, rs7690296 and rs11097431, were genotyped using Mass-Array SNP genotyping by Sequenom technology in 244 bipolar disorder patients, 471 schizophrenia patients, and 601 control individuals who were Malay, Chinese, and Indian ethnic groups in the Malaysian population. A significant association was observed in allele frequency between the rs7690296 polymorphism and bipolar disorder in the Indian ethnic group [P=0.02, adjusted odds ratio (OR) 0.058, 95% confidence interval (CI) 0.36-0.93]. A significant association was also observed between the rs7690296 polymorphism and schizophrenia under the recessive model for both Malay (P=0.02, adjusted OR 1.86, 95% CI 1.12-3.10) and Indian (P=0.02, adjusted OR 1.92, 95% CI 1.10-3.37) ethnic groups. However, no association was detected between the rs11097431 polymorphism either with bipolar disorder or with schizophrenia. Therefore, it can be deduced that the nonsynonymous rs7690296 polymorphism could play an important role in the pathophysiology of both bipolar disorder and schizophrenia.

Matched MeSH terms: Gene Frequency/genetics
Fulltext Distribution of the Duffy genotypes in Malaysian Borneo and its relation to Plasmodium knowlesi malaria susceptibility

de Silva JR, Amir A, Lau YL, Ooi CH, Fong MY

PLoS One, 2019;14(9):e0222681.
PMID: 31536563 DOI: 10.1371/journal.pone.0222681

The Duffy blood group plays a key role in Plasmodium knowlesi and Plasmodium vivax invasion into human erythrocytes. The geographical distribution of the Duffy alleles differs between regions with the FY*A allele having high frequencies in many Asian populations, the FY*B allele is found predominately in European populations and the FY*Bes allele found predominantly in African regions. A previous study in Peninsular Malaysia indicated high homogeneity of the dominant FY*A/FY*A genotype. However, the distribution of the Duffy genotypes in Malaysian Borneo is currently unknown. In the present study, the distribution of Duffy blood group genotypes and allelic frequencies among P. knowlesi infected patients as well as healthy individuals in Malaysian Borneo were determined. A total of 79 P. knowlesi patient blood samples and 76 healthy donor samples were genotyped using allele specific polymerase chain reaction (ASP-PCR). Subsequently a P. knowlesi invasion assay was carried out on FY*AB/ FY*A and FY*A/ FY*A Duffy genotype blood to investigate if either genotype conferred increased susceptibility to P. knowlesi invasion. Our results show almost equal distribution between the homozygous FY*A/FY*A and heterozygous FY*A/FY*B genotypes. This is in stark contrast to the Duffy distribution in Peninsular Malaysia and the surrounding Southeast Asian region which is dominantly FY*A/FY*A. The mean percent invasion of FY*A/FY*A and FY*A/FY*B blood was not significantly different indicating that neither blood group confers increased susceptibility to P. knowlesi invasion.

Matched MeSH terms: Gene Frequency/genetics