Displaying publications 1 - 20 of 60 in total

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  1. Morphological and genetic variations of the freshwater leech, Hirudinaria spp., in Peninsular Malaysia
    Chong LK, Ong AH, Tan SG, Taranjeet KA, Peris MM, Sana AM, et al.
    Biochem Genet, 2014 Jun;52(5-6):283-95.
    PMID: 24535156 DOI: 10.1007/s10528-014-9647-8
    In this study the genetic diversity of local freshwater leeches (Hirudinaria spp.) was inferred using mtDNA COI gene analysis and compared with the gross external variations of 26 freshwater leech specimens obtained from the wild and leech farms. Based on a neighbor-joining tree generated from 516 COI base sequences, four distinct clades of Hirudinaria were seen with interspecific genetic divergence in the range of 7.6-14.5%. The external morphological variations based on the presence of stripes, location of gonopores, and anus separated the samples into four morphologically distinct groups matching the four clades obtained from the molecular data. Two black stripes at the ventral region were observed only in specimens found clustered with clades that contained the GenBank-reported H. manillensis, whereas the brown or dark green coloration without stripes on the ventral region was seen in samples that clustered with H. javanica and H. bpling clades.
  2. Predictors of difficulty in intubation in patients with obstructive sleep apnoea
    Wang CMZ, Pang KP, Tan SG, Pang KA, Pang EB, Cherilynn TYN, et al.
    Med J Malaysia, 2019 04;74(2):133-137.
    PMID: 31079124
    OBJECTIVE: To evaluate predictors of difficult intubation in patients with obstructive sleep apnoea (OSA).

    METHODOLOGY: Prospective series of 405 OSA patients (350 males/55 females) who had upper airway surgery. Procedures included functional endoscopic sinus surgery, septoplasty, turbinate reduction, palate/tonsil surgery, and/or tongue base surgery. Intubation difficulty (ID) was assessed using Mallampati grade, Laryngoscopic grade (Cormack and Lehane), and clinical parameters including BMI, neck circumference, thyromental distance, jaw adequacy, neck movements and glidescope grading.

    RESULTS: Mean age was 41.6 years old; mean BMI 26.6; mean neck circumference 44.5cm; mean Apnea Hypopnea Index (AHI) was 25.0; and mean LSAT 82%. The various laryngeal grades (based on Cormack and Lehane), grade 1 - 53 patients (12.9%), grade 2A - 127 patients (31.0%), grade 2B - 125 patients (30.5%), grade 3 - 93 patients (22.7%) and grade 4 - seven patients (1.7%); hence, 24.4% had difficulties in intubation. Parameters that adversely affected intubation were, age of the patient, opening of mouth, retrognathia, overbite, overjet, limited neck extension, thyromental distance, Mallampati grade, and macroglossia (p<0.001). Body mass index (BMI) (p=0.087), neck circumference (p=0.645), neck aches (p=0.728), jaw aches (p=0.417), tonsil size (p=0.048), and AHI (p=0.047) had poor correlation with intubation. BMI-adjusted for Asians and Caucasians, showed that Asians were more likely to have difficulties in intubation (adjusted OR = 4.6 (95%Confidence Interval: 1.05 to 20.06) (p=0.043), compared to the Caucasian group.

    CONCLUSION: This study illustrates that difficult intubation can be predicted pre-surgery in order to avert any anaesthetic morbidity.

  3. Fulltext Recycling of superfine resolution agarose gel
    Seng TY, Singh R, Faridah QZ, Tan SG, Alwee SS
    Genet. Mol. Res., 2013;12(3):2360-7.
    PMID: 23546970 DOI: 10.4238/2013.March.11.1
    Genetic markers are now routinely used in a wide range of applications, from forensic DNA analysis to marker-assisted plant and animal breeding. The usual practice in such work is to extract the DNA, prime the markers of interest, and sift them out by electrically driving them through an appropriate matrix, usually a gel. The gels, made from polyacrylamide or agarose, are of high cost, limiting their greater applications in molecular marker work, especially in developing countries where such technology has great potential. Trials using superfine resolution (SFR) agarose for SSR marker screening showed that it is capable of resolving SSR loci and can be reused up to 14 times, thus greatly reducing the cost of each gel run. Furthermore, for certain applications, low concentrations of agarose sufficed and switching to lithium borate buffer, instead of the conventional Tris-borate-ethylenediaminetetraacetic acid buffer, will further save time and cost. The 2.5% gel was prepared following the Agarose SFR(TM) manual by adding 2.5 g agarose powder into 100 mL 1X lithium borate buffer in a 250-mL flask with rapid stirring. Two midigels (105 x 83 mm, 17 wells) or 4 minigels (50 x 83 mm, 8 wells), 4 mm thickness can be prepared from 100 mL gel solution. A total of 1680 PCR products amplified using 140 SSR markers from oil palm DNA samples were tested in this study using SFR recycled gel. As average, the gel can be recycled 8 times with good resolution, but can be recycled up to 14 times before the resolutions get blurred.
  4. Fulltext Genetic dissection of sympatric populations of brown planthopper, Nilaparvata lugens (Stål), using DALP-PCR molecular markers
    Latif MA, Rafii MY, Mazid MS, Ali ME, Ahmed F, Omar MY, et al.
    ScientificWorldJournal, 2012;2012:586831.
    PMID: 22593700 DOI: 10.1100/2012/586831
    Direct amplified length polymorphism (DALP) combines the advantages of a high-resolution fingerprint method and also characterizing the genetic polymorphisms. This molecular method was also found to be useful in brown planthopper, Nilaparvata lugens species complex for the analysis of genetic polymorphisms. A total of 11 populations of Nilaparvata spp. were collected from 6 locations from Malaysia. Two sympatric populations of brown planthopper, N. lugens, one from rice and the other from a weed grass (Leersia hexandra), were collected from each of five locations. N. bakeri was used as an out group. Three oligonucleotide primer pairs, DALP231/DALPR'5, DALP234/DALPR'5, and DALP235/DALPR'5 were applied in this study. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on genetic distances for the 11 populations of Nilaparvata spp. revealed that populations belonging to the same species and the same host type clustered together irrespective of their geographical localities of capture. The populations of N. lugens formed into two distinct clusters, one was insects with high esterase activities usually captured from rice and the other was with low esterase activities usually captured from L. hexandra. N. bakeri, an out group, was the most isolated group. Analyses of principal components, molecular variance, and robustness also supported greatly to the findings of cluster analysis.
  5. Fulltext Food assimilated by two sympatric populations of the brown planthopper Nilaparvata lugens (Delphacidae) feeding on different host plants contaminates insect DNA detected by RAPD-PCR analysis
    Latif MA, Omar MY, Tan SG, Siraj SS, Ali ME, Rafii MY
    Genet. Mol. Res., 2012;11(1):30-41.
    PMID: 22290463 DOI: 10.4238/2012.January.9.4
    Contamination of insect DNA for RAPD-PCR analysis can be a problem because many primers are non-specific and DNA from parasites or gut contents may be simultaneously extracted along with that of the insect. We measured the quantity of food ingested and assimilated by two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice and the other from Leersia hexandra (Poaceae), a wetland forage grass, and we also investigated whether host plant DNA contaminates that of herbivore insects in extractions of whole insects. Ingestion and assimilation of food were reduced significantly when individuals derived from one host plant were caged on the other species. The bands, OPA3 (1.25), OPD3 (1.10), OPD3 (0.80), OPD3 (0.60), pUC/M13F (0.35), pUC/M13F (0.20), BOXAIR (0.50), peh#3 (0.50), and peh#3 (0.17) were found in both rice-infesting populations of brown planthopper and its host plant (rice). Similarly, the bands, OPA4 (1.00), OPB10 (0.70), OPD3 (0.90), OPD3 (0.80), OPD3 (0.60), pUC/ M13F (0.35), pUC/M13F (0.20), and BOXAIR (0.50) were found in both Leersia-infesting populations of brown planthopper and the host plant. So, it is clear that the DNA bands amplified in the host plants were also found in the extracts from the insects feeding on them.
  6. Telescopium telescopium as potential biomonitors of Cu, Zn, and Pb for the tropical intertidal area
    Yap CK, Noorhaidah A, Azlan A, Nor Azwady AA, Ismail A, Ismail AR, et al.
    Ecotoxicol Environ Saf, 2009 Feb;72(2):496-506.
    PMID: 18243309 DOI: 10.1016/j.ecoenv.2007.12.005
    The distributions of Cu, Zn, and Pb concentrations in the selected soft tissues (foot, cephalic tentacle, mantle, muscle, gill, digestive caecum, and remaining soft tissues) and shells of the mud-flat snail Telescopium telescopium were determined in snails from eight geographical sites in the south-western intertidal area of Peninsular Malaysia. Generally, the digestive caecum compared with other selected soft tissues, accumulated higher concentration of Zn (214.35+/-14.56 microg/g dry weight), indicating that the digestive caecum has higher affinity for the essential Zn to bind to metallothionein. The shell demonstrated higher concentrations of Pb (41.23+/-1.20 microg/g dry weight) when compared to the selected soft tissues except gill from Kuala Sg. Ayam (95.76+/-5.32 microg/g dry weight). The use of different soft tissues also can solve the problem of defecation to reduce error in interpreting the bioavailability of heavy metals in the intertidal area.
  7. Genetic diversity of Asian water buffalo (Bubalus bubalis): mitochondrial DNA D-loop and cytochrome b sequence variation
    Lau CH, Drinkwater RD, Yusoff K, Tan SG, Hetzel DJ, Barker JS
    Anim. Genet., 1998 Aug;29(4):253-64.
    PMID: 9745663
    Swamp and river buffalo mitochondrial DNA (mtDNA) was sequenced for 303 bp of the cytochrome b gene for 54 animals from 14 populations, and for 158 bp of the D-loop region for 80 animals from 11 populations. Only one cytochrome b haplotype was found in river buffalo. Of the four haplotypes identified in swamp buffalo, one found in all populations is apparently ancestral both to the other swamp haplotypes and to the river haplotype. The phylogenetic relationships among the 33 D-loop haplotypes, with a cluster of 11 found in swamp buffalo only, also support the evolution of domesticated swamp and river buffalo from an ancestral swamp-like animal, most likely represented today by the wild Asian buffalo (Bubalus arnee). The time of divergence of the swamp and river types, estimated from the D-loop data, is 28,000 to 87,000 years ago. We hypothesise that the species originated in mainland south-east Asia, and that it spread north to China and west to the Indian subcontinent, where the rive type evolved and was domesticated. Following domestication in China, the domesticated swamp buffalo spread through two separate routes, through Taiwan and the Philippines to the eastern islands of Borneo and Sulawesi, and south through mainland south-east Asia and then to the western islands of Indonesia.
  8. Population genetic analysis of host seeking and resting behaviors in the malaria vector, Anopheles balabacensis (Diptera: Culicidae)
    Hii JL, Chew M, Sang VY, Munstermann LE, Tan SG, Panyim S, et al.
    J Med Entomol, 1991 Sep;28(5):675-84.
    PMID: 1682492
    During the intermonsoon period from mid-September to mid-October 1986, wild-caught Anopheles balabacensis Baisas females were marked and released in a host-choice experiment. Association between capture and recapture of marked mosquitoes from human and bovid hosts and blood meal host identification of recaptured females were determined on a daily basis. Although the mark-recapture and blood meal data indicated behavioral heterogeneity between buffalo and human biters, restriction endonuclease fragment length polymorphism analysis revealed no differences in repeat sequence profiles. Doubly-marked recaptures strongly indicated a "learning" component involved in a separate host preference experiment. In a "habitat loyalty" experiment conducted in January 1987, females of An. balabacensis preferentially returned to the resting sites (indoor surfaces and exit traps) where they were first caught. Of nine isozyme loci found to be polymorphic, the genotypic frequencies of Esterase-3 and Isocitrate dehydrogenase-3 were different in "faithfully" endophilic and exophilic subpopulations. Genetic heterozygosity, as determined by polyacrylamide gel electrophoresis, was greater in exophilic than endophilic population components. These results confirm that genetic and learning components can significantly influence house resting and host seeking behavior and may contribute to local epidemiological patterns of malaria transmission observed in Sabah, Malaysia.
  9. Biochemical genetic markers in the Kadazans of Sabah, Malaysia
    Tan SG, Teng YS, Ganesan J, Lau KY, Lie-Injo LE
    Hum Genet, 1979 Jul 18;49(3):349-53.
    PMID: 289626
    Kadazans, the largest indigenous group in Sabah, northern Borneo, were surveyed for glyoxalase I, phosphoglucomutase I, red cell acid phosphatase, esterase D, adenosine deaminase, soluble glutamate pyruvate transaminase, soluble glutamate oxaloacetate transaminase, 6-phosphogluconate dehydrogenase, uridine monophosphate kinase, adenylate kinase, peptidase B and D, superoxide dismutase, C5, group specific component, haptoglobin and transferrin. Kadazans were found to be polymorphic for GLO I, PGM I, RCAP, esterase D, ADA, s-Gpt, 6PGD, UMPK, Gc, C5, haptoglobin and peptidase B. Rare variants were found for transferrin and peptidase D. No variant was found for s-Got, SOD and AK.
  10. Genetic markers in Malaysians: variants of soluble and mitochondrial glutamic oxaloacetic transaminase and salivary and pancreatic amylase, phosphoglucomutase III and saliva esterase polymorphisms
    Teng YS, Tan SG, Lopez CG, Ng T, Lie-Injo LE
    Hum Genet, 1978 Apr 24;41(3):347-54.
    PMID: 649160
    Malaysians of Malay, Chinese, and Indian ancestries were electrophoretically phenotyped for Amy1 and saliva esterase region 1 (Set-1) from saliva, Amy2 from plasma, soluble and mitochondrial GOT and PGM3 from leukocyte and placenta. Kadazans and Bajaus, the indigenous people of Sabah, East Malaysia were surveyed for Amy2. Three types of variants were observed for Amy1, one type for Amy2. Only Indians were found to be polymorphic for Amy1. Two GOTs 2-1 and three GOTm 2-1 variants were found among 281 Chinese while three GOTm 2-1 variants were found among 311 Malays. Malaysian Malays, Chinese, and Indians were found to be polymorphic for Set-1 and PGM3. The gene frequencies in Malays are Set-1F=0.601 +/- 0.021, Set-1S = 0.399 +/- 0.021; PGM13 = 0.788 +/- 0.020, PGM23 = 0.212 +/- 0.020; in Chinese Set-1F = 0.497 +/- 0.028, Set-1S = 0.503 +/- 0.028; PGM13 = 0.745 +/- 0.24, PGM23 = 0.255 +/- 0.024; in Indians, Set-1F = 0.449 +/- 0.031, Set-1S = 0.551 +/- 0.031; PGM13 = 0.755 +/- 0.029, PGM23 = 0.245 +/- 0.029.
  11. Genetic studies of water buffalo blood markers. I. Red cell acid phosphatase, albumin, catalase, red cell alpha-esterase-3, group-specific component, and protease inhibitor
    Tan SG, Barker JS, Selvaraj OS, Mukherjee TK, Wong YF
    Biochem Genet, 1993 Jun;31(5-6):223-30.
    PMID: 8259925
    We have developed the methodologies for typing and family studies to establish the modes of inheritance of water buffalo red cell acid phosphatase (Acp), protease inhibitor (Pi), and group-specific component (Gc) on isoelectric focusing and albumin (Alb), red cell alpha-esterase-3 (Est-3), and catalase (Cat) on polyacrylamide gel electrophoresis. Family studies showed that Pi, Gc, Alb, and Cat are coded by autosomal genes with two codominant alleles, while Est-3 is autosomal with two codominant alleles and a recessive null allele and Acp exhibits three codominant alleles.
  12. Fulltext The effects of different velogenic NDV infections on the chicken bursa of Fabricius
    Kristeen-Teo YW, Yeap SK, Tan SW, Omar AR, Ideris A, Tan SG, et al.
    BMC Vet Res, 2017 May 31;13(1):151.
    PMID: 28569155 DOI: 10.1186/s12917-017-1071-y
    BACKGROUND: Virulent Newcastle disease virus (NDV) was reported to cause rapid depletion of chicken bursa of Fabricius. Severe pathological condition of the organ is commonly associated with high levels of virus replication, intense inflammatory response and also the degree of apoptosis. In this study, the responses of chicken bursa of Fabricius infected with two different strains of velogenic NDV, namely AF2240 and IBS002, were investigated by observing cell population changes, oxidative stress, viral replication and cytokine expression in the organ. Subsequently, apoptosis of enriched bursal IgM+ cells was determined to help us elucidate possible host pathogen relationships between the chicken bursa of Fabricius and NDV infection.

    RESULTS: The depletion of IgM+ cells and infiltration of macrophages were observed to be higher in bursa infected with AF2240 as compared to IBS002. In line with the increment of the macrophage population, higher nitric oxide (NO) and malondialdehyde (MDA) contents which indicated higher oxidative stress were also detected in bursa infected with NDV AF2240. In addition, higher pro-inflammatory cytokines and chemokine gene expression such as chicken CXCLi2, IL-18 and IFN-γ were observed in AF2240 infected bursa. Depletion of IgM+ cells was further confirmed with increased cell death and apoptosis of the cells in AF2240 infected bursa as compared to IBS002. However, it was found that the viral load for NDV strain IBS002 was comparatively higher than AF2240 although the magnitude of the pro- inflammatory cytokines expression and cell apoptosis was lower than AF2240.

    CONCLUSION: The results of our study demonstrated that infection of NDV strains AF2240 and IBS002 caused apoptosis in bursa IgM+ cells and its severity was associated with increased expression of pro-inflammatory cytokines/chemokine, macrophage infiltration and oxidative stress as the infection duration was prolonged. However, of the two viruses, we observed that NDV AF2240 induced a greater magnitude of apoptosis in chicken bursa IgM+ cells in comparison to IBS002. This might be due to the high level of oxidative stress and inflammatory cytokines/chemokine as well as lower IL10 expression which subsequently led to a high rate of apoptosis in the chicken bursa of Fabricius although the detected viral load of AF2240 was lower than IBS002.

  13. Fulltext Discovery of novel genic-SSR markers from transcriptome dataset of an important non-human primate, Macaca fascicularis
    Chang W, Ee-Uli J, Ng WL, Rovie-Ryan JJ, Tan SG, Yong CSY
    Sci Rep, 2019 06 11;9(1):8504.
    PMID: 31186469 DOI: 10.1038/s41598-019-44870-4
    Macaca fascicularis, also known as the cynomolgus macaque, is an important non-human primate animal model used in biomedical research. It is an Old-World primate widely distributed in Southeast Asia and is one of the most abundant macaque species in Malaysia. However, the genetic structure of wild cynomolgus macaque populations in Malaysia has not been thoroughly elucidated. In this study, we developed genic-simple sequence repeat (genic-SSR) markers from an in-house transcriptome dataset generated from the Malaysian cynomolgus macaque via RNA sequencing, and applied these markers on 26 cynomolgus macaque individuals. A collection of 14,751 genic-SSRs were identified, where 13,709 were perfect SSRs. Dinucleotide repeats were the most common repeat motifs with a frequency of 65.05%, followed by trinucleotide repeats (20.55%). Subsequently, we designed 300 pairs of primers based on perfect di- and trinucleotide SSRs, in which 105 SSRs were associated with functional genes. A subset of 30 SSR markers were randomly selected and validated, yielding 19 polymorphic markers with an average polymorphism information content value of 0.431. The development of genic-SSR markers in this study is indeed timely to provide useful markers for functional and population genetic studies of the cynomolgus macaque and other related non-human primate species.
  14. An investigation of arsenic contamination in Peninsular Malaysia based on Centella asiatica and soil samples
    Ong GH, Yap CK, Maziah M, Suhaimi H, Tan SG
    Environ Monit Assess, 2013 Apr;185(4):3243-54.
    PMID: 22821327 DOI: 10.1007/s10661-012-2787-6
    The first objective of this study was to provide data of arsenic (As) levels in Peninsular Malaysia based on soil samples and accumulation of As in Centella asiatica collected from 12 sampling sites in Peninsular Malaysia. The second objective was to assess the accumulation of As in transplanted C. asiatica between control and semi-polluted or polluted sites. Four sites were selected which were UPM (clean site), Balakong (semi-polluted site), Seri Kembangan (semi-polluted site) and Juru (polluted site). The As concentrations of plant and soil samples were determined by Instrumental Neutron Activation Analysis. The As levels ranged from 9.38 to 57.05 μg/g dw in soils, 0.21 to 4.33 μg/g dw in leaves, 0.18 to 1.83 μg/g dw in stems and 1.32-20.76 μg/g dw in roots. All sampling sites had As levels exceeding the CCME guideline (12 μg/g dw) except for Kelantan, P. Pauh, and Senawang with P. Klang having the highest As in soil (57.05 μg/g dw). In C. asiatica, As accumulation was highest in roots followed by leaves and stems. When the As level in soils were higher, the uptake of As in plants would also be increased. After the transplantation of plants to semi-polluted and polluted sites for 3 weeks, all concentration factors were greater than 50 % of the initial As level. The elimination factor was around 39 % when the plants were transplanted back to the clean sites for 3 weeks. The findings of the present study indicated that the leaves, stems and roots of C. asiatica are ideal biomonitors of As contamination. The present data results the most comprehensive data obtained on As levels in Malaysia.
  15. Development of single-locus DNA microsatellite markers using 5'anchored ISSR-PCR method for the mangrove horseshoe crab, Carcinoscorpius rotundicauda (Latreille, 1802) in Peninsular Malaysia
    Adibah AB, Ling LP, Tan SG, Faridah QZ, Christianus A
    Mol Biol Rep, 2012 Apr;39(4):3815-20.
    PMID: 21744263 DOI: 10.1007/s11033-011-1159-6
    Horseshoe crabs are said to be declining worldwide. However, there is still no published report on the status of horseshoe crabs in Malaysia. Thus, we report here eight informative microsatellite markers that were developed using the 5'-anchored ISSR-PCR enrichment procedure to diagnose the population genetic structure of the mangrove horseshoe crab, Carcinoscorpius rotundicauda from Peninsular Malaysia. This set of markers was tested on 127 samples and showed polymorphism in this species. Hence they should be useful in future essential population genetic studies of these living fossils in the Southeast Asian region.
  16. Eleven novel polymorphic microsatellite DNA markers from the green-lipped mussel Perna viridis
    Ong CC, Teh CH, Tan SG, Yusoff K, Yap CK
    Genetika, 2008 Apr;44(4):574-6.
    PMID: 18666563
    We report on the characterization of 11 polymorphic microsatellite loci in P. viridis, the first set of such markers developed and characterized for this species. The number of alleles per locus ranged from 2 to 7, whereas the observed heterozygosity ranged from 0.0447 to 0.4837. These markers should prove useful as powerful genetic markers for this species.
  17. Isolation of trinucleotide microsatellite markers for Mystus nemurus
    Hoh BP, Siraj SS, Tan SG, Yusoff K
    Genetika, 2008 Mar;44(3):427-9.
    PMID: 18664151
    Twelve single locus trinucleotide microsatellite markers were developed to characterize the Asian river catfish, Mystus nemurus, an important food fish in South East Asia. They were obtained by using a rapid method namely the 5' anchored PCR enrichment protocol. The specific primers were designed to flank the repeat sequences and these were subsequently used to characterize 90 unrelated fish from Malaysia. The number of alleles per locus ranged from 2 (MnVj2-281) to 12 (MnBp8-4-43b) while the levels of heterozygosity ranged from 0.0444 (MnVj2-1-19) to 0.7458 (MnVj2-291).
  18. Isolation and characterization of microsatellite loci in the Malaysian giant freshwater prawn, Macrobrachium rosenbergii
    Bhassu S, See LM, Hassan R, Siraj SS, Tan SG
    Mol Ecol Resour, 2008 Sep;8(5):983-5.
    PMID: 21585948 DOI: 10.1111/j.1755-0998.2008.02127.x
    Eight single locus microsatellite markers were developed to characterize the Malaysian giant freshwater prawn, Macrobrachium rosenbergii. These microsatellites were isolated from an enriched genomic library contained by using a 5'-anchored polymerase chain reaction technique. Primers were designed to flank the repeat sequences and subsequently used to characterize 30 unrelated individuals of the giant freshwater prawn. The polymerase chain reaction amplification products of these eight microsatellite loci were polymorphic with the number of alleles ranging from two to 10 alleles per locus while the levels of heterozygosity ranged from 0.6333 to 0.8667.
  19. Patterns of rapd markers and heavy metal concentrations in Perna viridis (L.), collected from metal-contaminated and uncontaminated coastal waters: are they correlated with each other?
    Yap CK, Chua BH, Teh CH, Tan SG, Ismail A
    Genetika, 2007 May;43(5):668-74.
    PMID: 17633561
    Genetic variation due to heavy metal contamination has always been an interesting topic of study. Because of the numerous contaminants being found in coastal and intertidal waters, there is always much discussion and argument as to which contaminant(s) caused the variations in the genetic structures of biomonitors. This study used a Single Primer Amplification Reaction (SPAR) technique namely Random Amplified Polymorphic DNA (RAPD) to determine the genetic diversity of the populations of the green-lipped mussel Perna viridis collected from a metal-contaminated site at Kg. Pasir Puteh and those from four relatively' uncontaminated sites (reference sites). Heavy metal levels (Cd, Cu, Pb and Zn) were also measured in the soft tissues and byssus of the mussels from all the sites. Cluster analyses employing UPGMA done based on the RAPD makers grouped the populations into two major clusters; the Bagan Tiang, Pantai Lido, Pontian and Kg. Pasir Puteh populations were in one cluster, while the Sg. Belungkor population clustered by itself. This indicated that the genetic diversity based on bands resulting from the use of all four RAPD primers on P. viridis did not indicate its potential use as a biomarker of heavy metal pollution in coastal waters. However, based on a correlation analysis between a particular metal and a band resulting from a specific RAPD primer revealed some significant (P < 0.01) correlations between the primers and the heavy metal concentrations in the byssus and soft tissues. Thus, the correlation between a particular metal and the bands resulting from the use of a specific RAPD primer on P. viridis could be used as biomonitoring tool of heavy metal pollution.
  20. Morphological and allozyme studies of small terrestrial snails (Opeas sp., Subulina sp. and Huttonella bicolor) collected from Peninsular Malaysia
    Choh MS, Yap CK, Tan SG, Jambari HA
    Genetika, 2006 Jan;42(1):49-57.
    PMID: 16523665
    Shell morphological characters and allozyme electrophoresis were used to study the relationships among six geographical populations of land snails collected from Peninsular Malaysia. Allozyme electrophoresis was used to study the genetic variations to complement the morphological features studied that included shell lengths, numbers of whorls and shell colour. Ten loci coding for six enzymes (MDH, LAP, ALP, PGM, G6PDH and EST) could be reliably scored in samples from the six populations studied. The dendrogram showed two major clusters with one cluster comprising Subulinidae populations from Perak, Selangor, Johor, Terengganu and Pahang while the other cluster included only the Streptaxidae Huttonella bicolor (red) population. The Subulinidae populations were grouped into two subclusters: one subcluster included the Subulina sp. populations from Perak, Selangor an Johor while the other subcluster included the Opeas sp. populations from Terengganu and Pahang. Morphological features can identify the different families and therefore they can complement the allozyme genetic studies on the land snail populations. Like other reports in the literature, our results also underline the importance of a genetic approach in conjunction with a morphological approach, for discriminating land snail species. The present results suggest that small land snails, which were similar in colour but different in sizes, were not of the same family/genus.
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