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  1. Principles and scope of population genetics in the study of vector mosquitoes
    Yong HS
    Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):657-9.
    PMID: 3070769
    Matched MeSH terms: Insect Vectors/genetics*
  2. Field studies of the bionomics of Anopheles maculatus and its role in malaria transmission in Malaysia
    Loong KP, Chiang GL, Yap HH
    Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):724.
    PMID: 3238487
    Matched MeSH terms: Insect Vectors/genetics
  3. Fulltext Oral ingestion of transgenic RIDL Ae. aegypti larvae has no negative effect on two predator Toxorhynchites species
    Nordin O, Donald W, Ming WH, Ney TG, Mohamed KA, Halim NA, et al.
    PLoS One, 2013;8(3):e58805.
    PMID: 23527029 DOI: 10.1371/journal.pone.0058805
    Dengue is the most important mosquito-borne viral disease. No specific treatment or vaccine is currently available; traditional vector control methods can rarely achieve adequate control. Recently, the RIDL (Release of Insect carrying Dominant Lethality) approach has been developed, based on the sterile insect technique, in which genetically engineered 'sterile' homozygous RIDL male insects are released to mate wild females; the offspring inherit a copy of the RIDL construct and die. A RIDL strain of the dengue mosquito, Aedes aegypti, OX513A, expresses a fluorescent marker gene for identification (DsRed2) and a protein (tTAV) that causes the offspring to die. We examined whether these proteins could adversely affect predators that may feed on the insect. Aedes aegypti is a peri-domestic mosquito that typically breeds in small, rain-water-filled containers and has no specific predators. Toxorhynchites larvae feed on small aquatic organisms and are easily reared in the laboratory where they can be fed exclusively on mosquito larvae. To evaluate the effect of a predator feeding on a diet of RIDL insects, OX513A Ae. aegypti larvae were fed to two different species of Toxorhynchites (Tx. splendens and Tx. amboinensis) and effects on life table parameters of all life stages were compared to being fed on wild type larvae. No significant negative effect was observed on any life table parameter studied; this outcome and the benign nature of the expressed proteins (tTAV and DsRed2) indicate that Ae. aegypti OX513A RIDL strain is unlikely to have any adverse effects on predators in the environment.
    Matched MeSH terms: Insect Vectors/genetics
  4. Fulltext Open field release of genetically engineered sterile male Aedes aegypti in Malaysia
    Lacroix R, McKemey AR, Raduan N, Kwee Wee L, Hong Ming W, Guat Ney T, et al.
    PLoS One, 2012;7(8):e42771.
    PMID: 22970102 DOI: 10.1371/journal.pone.0042771
    Dengue is the most important mosquito-borne viral disease. In the absence of specific drugs or vaccines, control focuses on suppressing the principal mosquito vector, Aedes aegypti, yet current methods have not proven adequate to control the disease. New methods are therefore urgently needed, for example genetics-based sterile-male-release methods. However, this requires that lab-reared, modified mosquitoes be able to survive and disperse adequately in the field.
    Matched MeSH terms: Insect Vectors/genetics*
  5. Genetically modified mosquitoes
    Aldridge S
    Nat Biotechnol, 2008 Jul;26(7):725.
    PMID: 18612284 DOI: 10.1038/nbt0708-725a
    Matched MeSH terms: Insect Vectors/genetics*
  6. 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.
    Matched MeSH terms: Insect Vectors/genetics*
  7. Genetic variation in the malaria mosquito vector Anopheles maculatus from Peninsular Malaysia
    Yong HS, Chiang GL, Loong KP, Ooi CS
    Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):681-7.
    PMID: 3238481
    Starch-gel electrophoretic studies on nine gene-enzyme systems comprising 14 loci revealed a fair level of genetic variation in two population samples of Anopheles maculatus from Peninsular Malaysia. The proportion of polymorphic loci was 0.36 for the Fort Bertau sample and 0.29 for the Gua Musang sample, while the mean heterozygosity value was 0.09 for Fort Bertau and 0.07 for Gua Musang. The values of genetic similarity (I = 0.98) and genetic distance (D = 0.02) were of the rank of geographical populations.
    Matched MeSH terms: Insect Vectors/genetics*
  8. Population cytogenetics of the malaria vector Anopheles leucosphyrus group
    Baimai V
    Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):667-80.
    PMID: 3238480
    Until recently, very little was known of Anopheles species complexes and their relationships to epidemiology and malaria transmission in Southeast Asia. During the past eight years, extensive studies on the genetics of natural populations of anopheline mosquitoes in this region, involving the interdisciplinary efforts of taxonomists, operational entomologists and biologists, have revealed groups of cryptic species of Anopheles vectors, particularly the An. leucos phyrus group. This species group comprise seventeen species and two subspecies widely distributed in the forested areas of Southeast Asia. Among these species. An. dirus Peyton and Harrison, has been shown by cytogenetic and morphological studies to be a complex of at least seven isomorphic species, provisionally designated species A, B, C, D, E, F and takasagoensis, on the Southeast Asian mainland. Cytological identification of these species is based on distinct banding patterns of salivary gland polytene chromosomes as well as heterochromatin differences in mitotic karyotypes. The five species found in Thailand (A-D, F) exhibit distinct geographic distributions. Species A is widespread throughout Thailand except in the south. Species B had been found in sympatry with species C in southern Thailand and both seem to show north-south clinal geographic variation. Species D is common on the west side of southern Thailand and along the Thai-Burmese border in sympatry with species A. Species F, An. nemophilous Peyton and Ramalingam, has been found in a population at the Thai-Malaysian border in this study although it was known to be common in southern and western Thailand and Peninsular Malaysia. Species E is known only from western India. The five species found in Thailand also exhibit seasonal variation in relative abundance and different nocturnal biting cycles. Chromosomal polymorphisms have been observed in mitotic and polytene chromosomes of An. dirus A and D. Species B and C also show heterochromatin variation in the sex chromosomes, but are monomorphic for the standard sequence in polytene chromosomes. These biological characteristics of the An. dirus complex may have implications for understanding the epidemiology of malaria in Southeast Asia. Recent cytogenetic studies of wild-caught samples of An. leucosphyrus from Sumatra, Kalimantan and southern Thailand have revealed the presence of two distinct species within this taxon. Species A is widely distributed in southern Thailand, East Malaysia and Kalimantan, while species B is confined to Sumatra. The two isomorphic species are vectors of human malaria within their range of distribution.(ABSTRACT TRUNCATED AT 400 WORDS)
    Matched MeSH terms: Insect Vectors/genetics*
  9. Enzyme polymorphism of the malaria vector, An. balabacensis (Diptera: Culicidae) revisited--why sample natural populations?
    Hii JL, Chew M, Vun YS, Nasir M, Chang MS
    Southeast Asian J. Trop. Med. Public Health, 1988 Dec;19(4):689-701.
    PMID: 3238482
    Two separate observations from recent electrophoretic studies of the systematics and population genetics of laboratory-reared populations which had a long history of colonization in various laboratories, were found to be inconsistent with the present study which used wild-caught populations from East Malaysia. Reanalysis of the two data sets generally indicated a low amount of genetic variation in laboratory colonies. The latter is characterized by higher frequency of monomorphic loci, low average heterozygosity values and, in one extreme case, no variability at two loci. However, natural populations of An. balabacensis and An. leucosphyrus showed more protein variability by the use of polyacrylamide gel electrophoresis. Since laboratory-maintained mosquitoes are genetically and phenotypically different from those in the field, results of laboratory studies on the systematics and population genetics of Anopheles species complexes may be biased.
    Matched MeSH terms: Insect Vectors/genetics*
  10. Quantitative trait loci in Anopheles gambiae controlling the encapsulation response against Plasmodium cynomolgi Ceylon
    Zheng L, Wang S, Romans P, Zhao H, Luna C, Benedict MQ
    BMC Genet, 2003 Oct 24;4:16.
    PMID: 14577840
    Anopheles gambiae females are the world's most successful vectors of human malaria. However, a fraction of these mosquitoes is refractory to Plasmodium development. L3-5, a laboratory selected refractory strain, encapsulates transforming ookinetes/early oocysts of a wide variety of Plasmodium species. Previous studies on these mosquitoes showed that one major (Pen1) and two minor (Pen2, Pen3) autosomal dominant quantitative trait loci (QTLs) control the melanotic encapsulation response against P. cynomolgi B, a simian malaria originating in Malaysia.
    Matched MeSH terms: Insect Vectors/genetics*
  11. Genetic diversity and DNA barcoding of the black fly (Diptera: Simuliidae) vectors of parasites causing human onchocerciasis in Guatemala
    Pramual P, Bunchom N, Saijuntha W, Tada I, Suganuma N, Agatsuma T
    Trop Biomed, 2019 Dec 01;36(4):938-957.
    PMID: 33597465
    Genetic variation based on mitochondrial cytochrome c oxidase I (COI) and II (COII) sequences was investigated for three black fly nominal species, Simulium metallicum Bellardi complex, S. callidum Dyar and Shannon, and S. ochraceum Walker complex, which are vectors of human onchocerciasis from Guatemala. High levels of genetic diversity were found in S. metallicum complex and S. ochraceum complex with maximum intraspecific genetic divergences of 11.39% and 4.25%, respectively. Levels of genetic diversity of these nominal species are consistent with species status for both of them as they are cytologically complexes of species. Phylogenetic analyses revealed that the S. metallicum complex from Guatemala divided into three distinct clades, two with members of this species from several Central and South American countries and another exclusively from Mexico. The Simulium ochraceum complex from Guatemala formed a clade with members of this species from Mexico and Costa Rica while those from Ecuador and Colombia formed another distinct clade. Very low diversity in S. callidum was found for both genes with maximum intraspecific genetic divergence of 0.68% for COI and 0.88% for COII. Low genetic diversity in S. callidum might be a consequence of the result being informative of only recent population history of the species.
    Matched MeSH terms: Insect Vectors/genetics
  12. SCAR markers and multiplex PCR-based identification of isomorphic species in the Anopheles dirus complex in Southeast Asia
    Manguin S, Kengne P, Sonnier L, Harbach RE, Baimai V, Trung HD, et al.
    Med Vet Entomol, 2002 Mar;16(1):46-54.
    PMID: 11963981
    The Anopheles dirus Peyton & Harrison complex of mosquitoes (Diptera: Culicidae) comprises seven known species, including important malaria vectors in Southeast Asia. Specific identification of each species of the complex, which cannot be distinguished using morphological characters, is crucial for understanding vector ecology and implementing effective control measures. Derived from individual random amplified polymorphic DNA (RAPD) markers, sequence characterized amplified regions (SCAR) were analysed for the design of specific paired-primers. Combination of six SCAR primers resulted in the development of a simple, robust, single multiplex PCR able to identify three important malaria vectors among the four most common species (A, B, C, D) of the complex: species A from several Southeast Asian countries, species B from Perlis, Malaysia, and species C and D from Thailand.
    Matched MeSH terms: Insect Vectors/genetics*
  13. Fulltext Detection of Wolbachia from field collected Aedes albopictus Skuse in Malaysia
    Noor Afizah A, Roziah A, Nazni WA, Lee HL
    Indian J Med Res, 2015 Aug;142(2):205-10.
    PMID: 26354218 DOI: 10.4103/0971-5916.164259
    Wolbachia-based vector control strategies have been proposed as a mean to augment the existing measures for controlling dengue vector. Prior to utilizing Wolbachia in novel vector control strategies, it is crucial to understand the Wolbachia-mosquito interactions. Many studies have only focused on the prevalence of Wolbachia in female Aedes albopictus with lack of attention on Wolbachia infection on the male Ae. albopictus which also affects the effective expression of Wolbachia induced- cytoplasmic incompatibility (CI). In this study, field surveys were conducted to screen for the infection status of Wolbachia in female and male Ae. albopictus from various habitats including housing areas, islands and seashore.
    Matched MeSH terms: Insect Vectors/genetics
  14. First description of the male of Phlebotomus betisi Lewis and Wharton, 1963 (Diptera: Psychodidae)
    Khadri MS, Depaquit J, Bargues MD, Ferté H, Mas-coma S, Lee HL, et al.
    Parasitol Int, 2008 Sep;57(3):295-9.
    PMID: 18378490 DOI: 10.1016/j.parint.2008.01.003
    The male of Phlebotomus (Larroussius) betisi is described from Malayan caves. Several males have been caught in association with P. betisi females. Males and females have been associated by ecology, biogeography, morphology and molecular biology (homology of the ND4 mtDNA sequences).
    Matched MeSH terms: Insect Vectors/genetics
  15. Molecular identification of Anopheles (Cellia) sundaicus from the Andaman and Nicobar islands of India
    Alam MT, Das MK, Ansari MA, Sharma YD
    Acta Trop, 2006 Jan;97(1):10-8.
    PMID: 16125659
    Anopheles (Cellia) sundaicus (Rodenwaldt) is an important malaria vector in the Andaman and Nicobar islands of India where it breeds in freshwater as well as in brackish water. To establish the molecular identity of An. sundaicus on these islands we analyzed samples from four geographically isolated areas-Teressa, Nancowry, Car Nicobar and Katchal islands. PCR-amplification and nucleotide sequence analysis were performed for internal transcribed spacer 2 (ITS2) and domain-3 (D3) of 28S rRNA. The ITS2 region of An. sundaicus from all four islands was identical but different from An. sundaicus A of Vietnam and An. sundaicus s.s of Malaysia. Furthermore, freshwater and brackish water forms of An. sundaicus did not reveal any sequence variation. Similarly, the D3 sequences were identical among all An. sundaicus samples from the four islands. D3 sequences for a species of the Sundaicus Complex are reported here for the first time and thus could not be compared with other regional isolates of this species. In conclusion, probably only one member of the Sundaicus Complex exists on the Andaman and Nicobar islands, which breeds in freshwater as well as in brackish water and is different from the An. sundaicus A and Malaysian An. sundaicus s.s. The identification of a new sibling species of the Sundaicus Complex in these islands is significant from the viewpoint of vector control strategies.
    Matched MeSH terms: Insect Vectors/genetics
  16. Mitochondrial Cytochrome Oxidase I Gene Sequence Analysis of Aedes Albopictus in Malaysia
    Ismail NA, Dom NC, Ismail R, Ahmad AH, Zaki A, Camalxaman SN
    J Am Mosq Control Assoc, 2015 Dec;31(4):305-12.
    PMID: 26675451 DOI: 10.2987/moco-31-04-305-312.1
    A study was conducted to establish polymorphic variation of the mitochondrial DNA encoding the cytochrome oxidase subunit 1 (CO1) gene in Aedes albopictus isolated from 2 hot spot dengue-infested areas in the Subang Jaya District, Malaysia. A phylogenetic analysis was performed with the use of sequences obtained from USJ6 and Taman Subang Mas (TSM). Comparison of the local CO1 sequences with a laboratory strain (USM), alongside reference strains derived from the GenBank database revealed low genetic variation in terms of nucleotide differences and haplotype diversity. Four methods were used to construct a phylogenetic tree and illustrate the genetic relationship of the 37 Ae. albopictus populations based on the CO1 sequences, namely neighbor-joining (NJ), maximum parsimony (MP), maximum likelihood (ML), and Bayesian method, which revealed a distinct relationship between isolates from USJ6 and TSM. Our findings provide new information regarding the genetic diversity among morphologically similar Ae. albopictus, which has not been reported to date.
    Matched MeSH terms: Insect Vectors/genetics*
  17. Fulltext Analysis of nuclear and organellar genomes of Plasmodium knowlesi in humans reveals ancient population structure and recent recombination among host-specific subpopulations
    Diez Benavente E, Florez de Sessions P, Moon RW, Holder AA, Blackman MJ, Roper C, et al.
    PLoS Genet, 2017 Sep;13(9):e1007008.
    PMID: 28922357 DOI: 10.1371/journal.pgen.1007008
    The macaque parasite Plasmodium knowlesi is a significant concern in Malaysia where cases of human infection are increasing. Parasites infecting humans originate from genetically distinct subpopulations associated with the long-tailed (Macaca fascicularis (Mf)) or pig-tailed macaques (Macaca nemestrina (Mn)). We used a new high-quality reference genome to re-evaluate previously described subpopulations among human and macaque isolates from Malaysian-Borneo and Peninsular-Malaysia. Nuclear genomes were dimorphic, as expected, but new evidence of chromosomal-segment exchanges between subpopulations was found. A large segment on chromosome 8 originating from the Mn subpopulation and containing genes encoding proteins expressed in mosquito-borne parasite stages, was found in Mf genotypes. By contrast, non-recombining organelle genomes partitioned into 3 deeply branched lineages, unlinked with nuclear genomic dimorphism. Subpopulations which diverged in isolation have re-connected, possibly due to deforestation and disruption of wild macaque habitats. The resulting genomic mosaics reveal traits selected by host-vector-parasite interactions in a setting of ecological transition.
    Matched MeSH terms: Insect Vectors/genetics
  18. Fulltext Microsatellite and mitochondrial markers reveal strong gene flow barriers for Anopheles farauti in the Solomon Archipelago: implications for malaria vector control
    Ambrose L, Cooper RD, Russell TL, Burkot TR, Lobo NF, Collins FH, et al.
    Int J Parasitol, 2014 Mar;44(3-4):225-33.
    PMID: 24440418 DOI: 10.1016/j.ijpara.2013.12.001
    Anopheles farauti is the primary malaria vector throughout the coastal regions of the Southwest Pacific. A shift in peak biting time from late to early in the night occurred following widespread indoor residue spraying of dichlorodiphenyltrichloro-ethane (DDT) and has persisted in some island populations despite the intervention ending decades ago. We used mitochondrial cytochrome oxidase I (COI) sequence data and 12 newly developed microsatellite markers to assess the population genetic structure of this malaria vector in the Solomon Archipelago. With geographically distinct differences in peak A. farauti night biting time observed in the Solomon Archipelago, we tested the hypothesis that strong barriers to gene flow exist in this region. Significant and often large fixation index (FST) values were found between different island populations for the mitochondrial and nuclear markers, suggesting highly restricted gene flow between islands. Some discordance in the location and strength of genetic breaks was observed between the mitochondrial and microsatellite markers. Since early night biting A. farauti individuals occur naturally in all populations, the strong gene flow barriers that we have identified in the Solomon Archipelago lend weight to the hypothesis that the shifts in peak biting time from late to early night have appeared independently in these disconnected island populations. For this reason, we suggest that insecticide impregnated bed nets and indoor residue spraying are unlikely to be effective as control tools against A. farauti occurring elsewhere, and if used, will probably result in peak biting time behavioural shifts similar to that observed in the Solomon Islands.
    Matched MeSH terms: Insect Vectors/genetics*
  19. Fulltext CPB1 of Aedes aegypti interacts with DENV2 E protein and regulates intracellular viral accumulation and release from midgut cells
    Tham HW, Balasubramaniam VR, Tejo BA, Ahmad H, Hassan SS
    Viruses, 2014 Dec;6(12):5028-46.
    PMID: 25521592 DOI: 10.3390/v6125028
    Aedes aegypti is a principal vector responsible for the transmission of dengue viruses (DENV). To date, vector control remains the key option for dengue disease management. To develop new vector control strategies, a more comprehensive understanding of the biological interactions between DENV and Ae. aegypti is required. In this study, a cDNA library derived from the midgut of female adult Ae. aegypti was used in yeast two-hybrid (Y2H) screenings against DENV2 envelope (E) protein. Among the many interacting proteins identified, carboxypeptidase B1 (CPB1) was selected, and its biological interaction with E protein in Ae. aegypti primary midgut cells was further validated. Our double immunofluorescent assay showed that CPB1-E interaction occurred in the endoplasmic reticulum (ER) of the Ae. aegypti primary midgut cells. Overexpression of CPB1 in mosquito cells resulted in intracellular DENV2 genomic RNA or virus particle accumulation, with a lower amount of virus release. Therefore, we postulated that in Ae. aegypti midgut cells, CPB1 binds to the E protein deposited on the ER intraluminal membranes and inhibits DENV2 RNA encapsulation, thus inhibiting budding from the ER, and may interfere with immature virus transportation to the trans-Golgi network.
    Matched MeSH terms: Insect Vectors/genetics
  20. Fulltext Pyrethroid Resistance in Malaysian Populations of Dengue Vector Aedes aegypti Is Mediated by CYP9 Family of Cytochrome P450 Genes
    Ishak IH, Kamgang B, Ibrahim SS, Riveron JM, Irving H, Wondji CS
    PLoS Negl Trop Dis, 2017 01;11(1):e0005302.
    PMID: 28114328 DOI: 10.1371/journal.pntd.0005302
    BACKGROUND: Dengue control and prevention rely heavily on insecticide-based interventions. However, insecticide resistance in the dengue vector Aedes aegypti, threatens the continued effectiveness of these tools. The molecular basis of the resistance remains uncharacterised in many endemic countries including Malaysia, preventing the design of evidence-based resistance management. Here, we investigated the underlying molecular basis of multiple insecticide resistance in Ae. aegypti populations across Malaysia detecting the major genes driving the metabolic resistance.

    METHODOLOGY/PRINCIPAL FINDINGS: Genome-wide microarray-based transcription analysis was carried out to detect the genes associated with metabolic resistance in these populations. Comparisons of the susceptible New Orleans strain to three non-exposed multiple insecticide resistant field strains; Penang, Kuala Lumpur and Kota Bharu detected 2605, 1480 and 425 differentially expressed transcripts respectively (fold-change>2 and p-value ≤ 0.05). 204 genes were commonly over-expressed with monooxygenase P450 genes (CYP9J27, CYP6CB1, CYP9J26 and CYP9M4) consistently the most up-regulated detoxification genes in all populations, indicating that they possibly play an important role in the resistance. In addition, glutathione S-transferases, carboxylesterases and other gene families commonly associated with insecticide resistance were also over-expressed. Gene Ontology (GO) enrichment analysis indicated an over-representation of GO terms linked to resistance such as monooxygenases, carboxylesterases, glutathione S-transferases and heme-binding. Polymorphism analysis of CYP9J27 sequences revealed a high level of polymorphism (except in Joho Bharu), suggesting a limited directional selection on this gene. In silico analysis of CYP9J27 activity through modelling and docking simulations suggested that this gene is involved in the multiple resistance in Malaysian populations as it is predicted to metabolise pyrethroids, DDT and bendiocarb.

    CONCLUSION/SIGNIFICANCE: The predominant over-expression of cytochrome P450s suggests that synergist-based (PBO) control tools could be utilised to improve control of this major dengue vector across Malaysia.

    Matched MeSH terms: Insect Vectors/genetics
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