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Overview of Aedes aegypti and Use in Laboratory Studies. Cold Spring Harb Protoc 2023; 2023:107651-pdb.top. [PMID: 36223992 DOI: 10.1101/pdb.top107651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The yellow fever mosquito Aedes aegypti is a prolific disease vector. This mosquito has been the subject of scientific investigation for more than a century. Continued research into Aedes aegypti biology is crucial for understanding how to halt the suite of major arthropod-borne viral diseases this mosquito transmits. Here, we provide an introductory overview of Aedes aegypti life cycle; evolutionary history, biology, and ecology; genetics and sex differences; vector competence; and laboratory colonization and considerations for rearing this robust mosquito species for use in laboratory research.
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2
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Dedkhad W, Bartholomay LC, Christensen BM, Joshi D, Taai K, Hempolchom C, Saeung A. Effects of cross-mating on susceptibility of synonymous mosquitoes, Anopheles paraliae and Anopheles lesteri to infection with nocturnally subperiodic Brugia malayi. Acta Trop 2018; 187:65-71. [PMID: 30055175 DOI: 10.1016/j.actatropica.2018.07.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/19/2018] [Accepted: 07/24/2018] [Indexed: 11/25/2022]
Abstract
In Southeast Asia, Anopheles lesteri (recently synonymized with An. paraliae) is a competent vector for Plasmodium parasites, but its ability to transmit parasites that cause lymphatic filariasis has yet to be determined. In this study, the susceptibility of An. lesteri and An. paraliae to Brugia malayi parasites was determined by comparing with the control mosquito, Aedes togoi. We found that the infection prevalence per infected mosquito in An. paraliae was significantly lower than that in Ae. togoi in all experiments (p < 0.05). Reciprocal crosses (female An. paraliae x male An. lesteri) produced highly susceptible F1-hybrid progeny, with increased infection prevalence when compared to parental stocks (p < 0.05). Subsequently, the possibilities of introgression between high and low/moderate parasite susceptibility genes were investigated by cross-mating experiments (parental, reciprocal crosses, back crosses and repeated backcrosses). The results showed the possibility of introgression of B. malayi-susceptible genes between An. paraliae (low/moderate susceptibility) and An. lesteri (high susceptibility) based on increasing or decreasing susceptibility and normal larval development in the thoracic muscles of F3-hybrids. Additionally, melanization, an innate immune response with proven involvement in the susceptibility or refractoriness of mosquitoes to B. malayi parasites, was examined. Parasite degeneration and cell aggregation, and melanization were observed for first-stage larvae in the thoracic muscle fibers of hybrid mosquitoes.
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Famakinde DO. Mosquitoes and the Lymphatic Filarial Parasites: Research Trends and Budding Roadmaps to Future Disease Eradication. Trop Med Infect Dis 2018; 3:E4. [PMID: 30274403 PMCID: PMC6136629 DOI: 10.3390/tropicalmed3010004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 12/26/2017] [Accepted: 12/27/2017] [Indexed: 11/17/2022] Open
Abstract
The mosquito-borne lymphatic filariasis (LF) is a parasitic, neglected tropical disease that imposes an unbearable human scourge. Despite the unprecedented efforts in mass drug administration (MDA) and morbidity management, achieving the global LF elimination slated for the year 2020 has been thwarted by limited MDA coverage and ineffectiveness in the chemotherapeutic intervention. Moreover, successful and sustainable elimination of mosquito-vectored diseases is often encumbered by reintroduction and resurgence emanating from human residual or new infections being widely disseminated by the vectors even when chemotherapy proves effective, but especially in the absence of effective vaccines. This created impetus for strengthening the current defective mosquito control approach, and profound research in vector⁻pathogen systems and vector biology has been pushing the boundaries of ideas towards developing refined vector-harnessed control strategies. Eventual implementation of these emerging concepts will offer a synergistic approach that will not only accelerate LF elimination, but also augurs well for its future eradication. This brief review focuses on advances in mosquito⁻filaria research and considers the emerging prospects for future eradication of LF.
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Affiliation(s)
- Damilare O Famakinde
- Department of Medical Microbiology and Parasitology, College of Medicine of the University of Lagos, Idi-Araba, Lagos 100254, Nigeria.
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4
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Stevens L, Yan G, Pray LA. CONSEQUENCES OF INBREEDING ON INVERTEBRATE HOST SUSCEPTIBILITY TO PARASITIC INFECTION. Evolution 2017; 51:2032-2039. [DOI: 10.1111/j.1558-5646.1997.tb05126.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/1997] [Accepted: 08/11/1997] [Indexed: 12/01/2022]
Affiliation(s)
- Lori Stevens
- Department of Biology University of Vermont Marsh Life Science Building Burlington Vermont 05405‐0086
| | - Guiyun Yan
- Department of Biology University of Vermont Marsh Life Science Building Burlington Vermont 05405‐0086
| | - Leslie A. Pray
- Department of Biology University of Vermont Marsh Life Science Building Burlington Vermont 05405‐0086
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Severson DW, Behura SK. Genome Investigations of Vector Competence in Aedes aegypti to Inform Novel Arbovirus Disease Control Approaches. INSECTS 2016; 7:insects7040058. [PMID: 27809220 PMCID: PMC5198206 DOI: 10.3390/insects7040058] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 11/16/2022]
Abstract
Dengue (DENV), yellow fever, chikungunya, and Zika virus transmission to humans by a mosquito host is confounded by both intrinsic and extrinsic variables. Besides virulence factors of the individual arboviruses, likelihood of virus transmission is subject to variability in the genome of the primary mosquito vector, Aedes aegypti. The “vectorial capacity” of A. aegypti varies depending upon its density, biting rate, and survival rate, as well as its intrinsic ability to acquire, host and transmit a given arbovirus. This intrinsic ability is known as “vector competence”. Based on whole transcriptome analysis, several genes and pathways have been predicated to have an association with a susceptible or refractory response in A. aegypti to DENV infection. However, the functional genomics of vector competence of A. aegypti is not well understood, primarily due to lack of integrative approaches in genomic or transcriptomic studies. In this review, we focus on the present status of genomics studies of DENV vector competence in A. aegypti as limited information is available relative to the other arboviruses. We propose future areas of research needed to facilitate the integration of vector and virus genomics and environmental factors to work towards better understanding of vector competence and vectorial capacity in natural conditions.
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Affiliation(s)
- David W Severson
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Susanta K Behura
- Division of Animal Sciences, University of Missouri, Columbia, MO 65211, USA.
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6
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Zamanian M, Andersen EC. Prospects and challenges of CRISPR/Cas genome editing for the study and control of neglected vector-borne nematode diseases. FEBS J 2016; 283:3204-21. [PMID: 27300487 PMCID: PMC5053252 DOI: 10.1111/febs.13781] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/05/2016] [Accepted: 06/13/2016] [Indexed: 01/19/2023]
Abstract
Neglected tropical diseases caused by parasitic nematodes inflict an immense health and socioeconomic burden throughout much of the developing world. Current estimates indicate that more than two billion people are infected with nematodes, resulting in the loss of 14 million disability-adjusted life years per annum. Although these parasites cause significant mortality, they primarily cause chronic morbidity through a wide range of severe clinical ailments. Treatment options for nematode infections are restricted to a small number of anthelmintic drugs, and the rapid expansion of anthelmintic mass drug administration raises concerns of drug resistance. Preservation of existing drugs is necessary, as well as the development of new treatment options and methods of control. We focus this review on how the democratization of CRISPR/Cas9 genome editing technology can be enlisted to improve our understanding of the biology of nematode parasites and our ability to treat the infections they cause. We will first explore how this robust method of genome manipulation can be used to newly exploit the powerful model nematode Caenorhabditis elegans for parasitology research. We will then discuss potential avenues to develop CRISPR/Cas9 editing protocols in filarial nematodes. Lastly, we will propose potential ways in which CRISPR/Cas9 can be used to engineer gene drives that target the transmission of mosquito-borne filarial nematodes.
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Affiliation(s)
- Mostafa Zamanian
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonILUSA
| | - Erik C. Andersen
- Department of Molecular BiosciencesNorthwestern UniversityEvanstonILUSA
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7
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Paiva MHS, Lovin DD, Mori A, Melo-Santos MAV, Severson DW, Ayres CFJ. Identification of a major Quantitative Trait Locus determining resistance to the organophosphate temephos in the dengue vector mosquito Aedes aegypti. Genomics 2015; 107:40-8. [PMID: 26576515 DOI: 10.1016/j.ygeno.2015.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 02/09/2023]
Abstract
Organophosphate insecticides (OP) have extensively been used to control mosquitoes, such as the vector Aedes aegypti. Unfortunately, OP resistance has hampered control programs worldwide. We used Quantitative Trait Locus (QTL) mapping to evaluate temephos resistance in two F1 intercross populations derived from crosses between a resistant Ae. aegypti strain (RecR) and two susceptible strains (MoyoD and Red). A single major effect QTL was identified on chromosome 2 of both segregating populations, named rtt1 (resistance to temephos 1). Bioinformatics analyses identified a cluster of carboxylesterase genes (CCE) within the rtt1 interval. qRT-PCR demonstrated that different CCEs were up-regulated in F2 resistant individuals from both crosses. However, none exceeded the 2-fold expression. Primary mechanisms for temephos resistance may vary between Ae. aegypti populations, yet also appear to support previous findings suggesting that multiple linked esterase genes may contribute to temephos resistance in the RecR strain as well as other populations.
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Affiliation(s)
- Marcelo H S Paiva
- Departamento de Entomologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Av. Professor Moraes Rego, s/n - Campus da UFPE - Cidade Universitária, Recife, PE50740-465, Brazil; Universidade Federal de Pernambuco, Centro Acadêmico do Agreste, Rodovia BR-104, km 59, Nova Caruaru, Caruaru, PE 55002-970, Brazil; Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556-5645, USA.
| | - Diane D Lovin
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556-5645, USA.
| | - Akio Mori
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556-5645, USA.
| | - Maria A V Melo-Santos
- Departamento de Entomologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Av. Professor Moraes Rego, s/n - Campus da UFPE - Cidade Universitária, Recife, PE50740-465, Brazil.
| | - David W Severson
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556-5645, USA.
| | - Constância F J Ayres
- Departamento de Entomologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz, Av. Professor Moraes Rego, s/n - Campus da UFPE - Cidade Universitária, Recife, PE50740-465, Brazil.
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8
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Naumenko AN, Timoshevskiy VA, Kinney NA, Kokhanenko AA, deBruyn BS, Lovin DD, Stegniy VN, Severson DW, Sharakhov IV, Sharakhova MV. Mitotic-chromosome-based physical mapping of the Culex quinquefasciatus genome. PLoS One 2015; 10:e0115737. [PMID: 25768920 PMCID: PMC4358980 DOI: 10.1371/journal.pone.0115737] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 11/21/2014] [Indexed: 11/28/2022] Open
Abstract
The genome assembly of southern house mosquito Cx. quinquefasciatus is represented by a high number of supercontigs with no order or orientation on the chromosomes. Although cytogenetic maps for the polytene chromosomes of this mosquito have been developed, their utilization for the genome mapping remains difficult because of the low number of high-quality spreads in chromosome preparations. Therefore, a simple and robust mitotic-chromosome-based approach for the genome mapping of Cx. quinquefasciatus still needs to be developed. In this study, we performed physical mapping of 37 genomic supercontigs using fluorescent in situ hybridization on mitotic chromosomes from imaginal discs of 4th instar larvae. The genetic linkage map nomenclature was adopted for the chromosome numbering based on the direct positioning of 58 markers that were previously genetically mapped. The smallest, largest, and intermediate chromosomes were numbered as 1, 2, and 3, respectively. For idiogram development, we analyzed and described in detail the morphology and proportions of the mitotic chromosomes. Chromosomes were subdivided into 19 divisions and 72 bands of four different intensities. These idiograms were used for mapping the genomic supercontigs/genetic markers. We also determined the presence of length polymorphism in the q arm of sex-determining chromosome 1 in Cx. quinquefasciatus related to the size of ribosomal locus. Our physical mapping and previous genetic linkage mapping resulted in the chromosomal assignment of 13% of the total genome assembly to the chromosome bands. We provided the first detailed description, nomenclature, and idiograms for the mitotic chromosomes of Cx. quinquefasciatus. Further application of the approach developed in this study will help to improve the quality of the southern house mosquito genome.
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Affiliation(s)
- Anastasia N. Naumenko
- Department of Entomology and Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Vladimir A. Timoshevskiy
- Department of Entomology and Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Nicholas A. Kinney
- Department of Genomics, Bioinformatics, and Computational Biology, Virginia Tech, Blacksburg, Virginia, United States of America
| | | | - Becky S. deBruyn
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Diane D. Lovin
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | | | - David W. Severson
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Igor V. Sharakhov
- Department of Entomology and Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Maria V. Sharakhova
- Department of Entomology and Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Institute of Biology and Biophysics, Tomsk State University, Tomsk, Russia
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9
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Juneja P, Ariani CV, Ho YS, Akorli J, Palmer WJ, Pain A, Jiggins FM. Exome and transcriptome sequencing of Aedes aegypti identifies a locus that confers resistance to Brugia malayi and alters the immune response. PLoS Pathog 2015; 11:e1004765. [PMID: 25815506 PMCID: PMC4376896 DOI: 10.1371/journal.ppat.1004765] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 02/25/2015] [Indexed: 11/18/2022] Open
Abstract
Many mosquito species are naturally polymorphic for their abilities to transmit parasites, a feature which is of great interest for controlling vector-borne disease. Aedes aegypti, the primary vector of dengue and yellow fever and a laboratory model for studying lymphatic filariasis, is genetically variable for its capacity to harbor the filarial nematode Brugia malayi. The genome of Ae. aegypti is large and repetitive, making genome resequencing difficult and expensive. We designed exome captures to target protein-coding regions of the genome, and used association mapping in a wild Kenyan population to identify a single, dominant, sex-linked locus underlying resistance. This falls in a region of the genome where a resistance locus was previously mapped in a line established in 1936, suggesting that this polymorphism has been maintained in the wild for the at least 80 years. We then crossed resistant and susceptible mosquitoes to place both alleles of the gene into a common genetic background, and used RNA-seq to measure the effect of this locus on gene expression. We found evidence for Toll, IMD, and JAK-STAT pathway activity in response to early stages of B. malayi infection when the parasites are beginning to die in the resistant genotype. We also found that resistant mosquitoes express anti-microbial peptides at the time of parasite-killing, and that this expression is suppressed in susceptible mosquitoes. Together, we have found that a single resistance locus leads to a higher immune response in resistant mosquitoes, and we identify genes in this region that may be responsible for this trait.
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Affiliation(s)
- Punita Juneja
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Cristina V. Ariani
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Yung Shwen Ho
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science & Technology, Thuwal, Kingdom of Saudi Arabia
| | - Jewelna Akorli
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - William J. Palmer
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Arnab Pain
- Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science & Technology, Thuwal, Kingdom of Saudi Arabia
| | - Francis M. Jiggins
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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10
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Powell JR, Tabachnick WJ. Genetic shifting: a novel approach for controlling vector-borne diseases. Trends Parasitol 2014; 30:282-8. [PMID: 24794113 DOI: 10.1016/j.pt.2014.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/02/2014] [Accepted: 04/02/2014] [Indexed: 12/25/2022]
Abstract
Rendering populations of vectors of diseases incapable of transmitting pathogens through genetic methods has long been a goal of vector geneticists. We outline a method to achieve this goal that does not involve the introduction of any new genetic variants to the target population. Rather we propose that shifting the frequencies of naturally occurring alleles that confer refractoriness to transmission can reduce transmission below a sustainable level. The program employs methods successfully used in plant and animal breeding. Because no artificially constructed genetically modified organisms (GMOs) are introduced into the environment, the method is minimally controversial. We use Aedes aegypti and dengue virus (DENV) for illustrative purposes but point out that the proposed program is generally applicable to vector-borne disease control.
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Affiliation(s)
- Jeffrey R Powell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 6520-8105, USA.
| | - Walter J Tabachnick
- Florida Medical Entomology Laboratory, University of Florida, Institute of Food and Agricultural Sciences (IFAS), Vero Beach, FL 32962, USA
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Choi YJ, Aliota MT, Mayhew GF, Erickson SM, Christensen BM. Dual RNA-seq of parasite and host reveals gene expression dynamics during filarial worm-mosquito interactions. PLoS Negl Trop Dis 2014; 8:e2905. [PMID: 24853112 PMCID: PMC4031193 DOI: 10.1371/journal.pntd.0002905] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 04/14/2014] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Parasite biology, by its very nature, cannot be understood without integrating it with that of the host, nor can the host response be adequately explained without considering the activity of the parasite. However, due to experimental limitations, molecular studies of parasite-host systems have been predominantly one-sided investigations focusing on either of the partners involved. Here, we conducted a dual RNA-seq time course analysis of filarial worm parasite and host mosquito to better understand the parasite processes underlying development in and interaction with the host tissue, from the establishment of infection to the development of infective-stage larva. METHODOLOGY/PRINCIPAL FINDINGS Using the Brugia malayi-Aedes aegypti system, we report parasite gene transcription dynamics, which exhibited a highly ordered developmental program consisting of a series of cyclical and state-transitioning temporal patterns. In addition, we contextualized these parasite data in relation to the concurrent dynamics of the host transcriptome. Comparative analyses using uninfected tissues and different host strains revealed the influence of parasite development on host gene transcription as well as the influence of the host environment on parasite gene transcription. We also critically evaluated the life-cycle transcriptome of B. malayi by comparing developmental stages in the mosquito relative to those in the mammalian host, providing insight into gene expression changes underpinning the mosquito-borne parasitic lifestyle of this heteroxenous parasite. CONCLUSIONS/SIGNIFICANCE The data presented herein provide the research community with information to design wet lab experiments and select candidates for future study to more fully dissect the whole set of molecular interactions of both organisms in this mosquito-filarial worm symbiotic relationship. Furthermore, characterization of the transcriptional program over the complete life cycle of the parasite, including stages within the mosquito, could help devise novel targets for control strategies.
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Affiliation(s)
- Young-Jun Choi
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Matthew T. Aliota
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - George F. Mayhew
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sara M. Erickson
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Bruce M. Christensen
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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12
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Timoshevskiy VA, Kinney NA, deBruyn BS, Mao C, Tu Z, Severson DW, Sharakhov IV, Sharakhova MV. Genomic composition and evolution of Aedes aegypti chromosomes revealed by the analysis of physically mapped supercontigs. BMC Biol 2014; 12:27. [PMID: 24731704 PMCID: PMC4021624 DOI: 10.1186/1741-7007-12-27] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 04/01/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND An initial comparative genomic study of the malaria vector Anopheles gambiae and the yellow fever mosquito Aedes aegypti revealed striking differences in the genome assembly size and in the abundance of transposable elements between the two species. However, the chromosome arms homology between An. gambiae and Ae. aegypti, as well as the distribution of genes and repetitive elements in chromosomes of Ae. aegypti, remained largely unexplored because of the lack of a detailed physical genome map for the yellow fever mosquito. RESULTS Using a molecular landmark-guided fluorescent in situ hybridization approach, we mapped 624 Mb of the Ae. aegypti genome to mitotic chromosomes. We used this map to analyze the distribution of genes, tandem repeats and transposable elements along the chromosomes and to explore the patterns of chromosome homology and rearrangements between Ae. aegypti and An. gambiae. The study demonstrated that the q arm of the sex-determining chromosome 1 had the lowest gene content and the highest density of minisatellites. A comparative genomic analysis with An. gambiae determined that the previously proposed whole-arm synteny is not fully preserved; a number of pericentric inversions have occurred between the two species. The sex-determining chromosome 1 had a higher rate of genome rearrangements than observed in autosomes 2 and 3 of Ae. aegypti. CONCLUSIONS The study developed a physical map of 45% of the Ae. aegypti genome and provided new insights into genomic composition and evolution of Ae. aegypti chromosomes. Our data suggest that minisatellites rather than transposable elements played a major role in rapid evolution of chromosome 1 in the Aedes lineage. The research tools and information generated by this study contribute to a more complete understanding of the genome organization and evolution in mosquitoes.
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Affiliation(s)
| | | | | | | | | | | | | | - Maria V Sharakhova
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.
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13
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Assembly of the genome of the disease vector Aedes aegypti onto a genetic linkage map allows mapping of genes affecting disease transmission. PLoS Negl Trop Dis 2014; 8:e2652. [PMID: 24498447 PMCID: PMC3907309 DOI: 10.1371/journal.pntd.0002652] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 12/05/2013] [Indexed: 11/19/2022] Open
Abstract
The mosquito Aedes aegypti transmits some of the most important human arboviruses, including dengue, yellow fever and chikungunya viruses. It has a large genome containing many repetitive sequences, which has resulted in the genome being poorly assembled - there are 4,758 scaffolds, few of which have been assigned to a chromosome. To allow the mapping of genes affecting disease transmission, we have improved the genome assembly by scoring a large number of SNPs in recombinant progeny from a cross between two strains of Ae. aegypti, and used these to generate a genetic map. This revealed a high rate of misassemblies in the current genome, where, for example, sequences from different chromosomes were found on the same scaffold. Once these were corrected, we were able to assign 60% of the genome sequence to chromosomes and approximately order the scaffolds along the chromosome. We found that there are very large regions of suppressed recombination around the centromeres, which can extend to as much as 47% of the chromosome. To illustrate the utility of this new genome assembly, we mapped a gene that makes Ae. aegypti resistant to the human parasite Brugia malayi, and generated a list of candidate genes that could be affecting the trait.
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14
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Timoshevskiy VA, Severson DW, deBruyn BS, Black WC, Sharakhov IV, Sharakhova MV. An integrated linkage, chromosome, and genome map for the yellow fever mosquito Aedes aegypti. PLoS Negl Trop Dis 2013; 7:e2052. [PMID: 23459230 PMCID: PMC3573077 DOI: 10.1371/journal.pntd.0002052] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/21/2012] [Indexed: 11/18/2022] Open
Abstract
Background Aedes aegypti, the yellow fever mosquito, is an efficient vector of arboviruses and a convenient model system for laboratory research. Extensive linkage mapping of morphological and molecular markers localized a number of quantitative trait loci (QTLs) related to the mosquito's ability to transmit various pathogens. However, linking the QTLs to Ae. aegypti chromosomes and genomic sequences has been challenging because of the poor quality of polytene chromosomes and the highly fragmented genome assembly for this species. Methodology/Principal Findings Based on the approach developed in our previous study, we constructed idiograms for mitotic chromosomes of Ae. aegypti based on their banding patterns at early metaphase. These idiograms represent the first cytogenetic map developed for mitotic chromosomes of Ae. aegypti. One hundred bacterial artificial chromosome clones carrying major genetic markers were hybridized to the chromosomes using fluorescent in situ hybridization. As a result, QTLs related to the transmission of the filarioid nematode Brugia malayi, the avian malaria parasite Plasmodium gallinaceum, and the dengue virus, as well as sex determination locus and 183 Mbp of genomic sequences were anchored to the exact positions on Ae. aegypti chromosomes. A linear regression analysis demonstrated a good correlation between positions of the markers on the physical and linkage maps. As a result of the recombination rate variation along the chromosomes, 12 QTLs on the linkage map were combined into five major clusters of QTLs on the chromosome map. Conclusion This study developed an integrated linkage, chromosome, and genome map—iMap—for the yellow fever mosquito. Our discovery of the localization of multiple QTLs in a few major chromosome clusters suggests a possibility that the transmission of various pathogens is controlled by the same genomic loci. Thus, the iMap will facilitate the identification of genomic determinants of traits responsible for susceptibility or refractoriness of the mosquito to diverse pathogens. About half of the human population is under risk of dengue infection. Because of the absence of a vaccine or drug treatment, the prevention of this disease largely relies on controlling its major vector mosquito Aedes aegypti. Availability of the complete genome sequence for this mosquito offers the potential to help in the identification of novel disease control strategies. An efficient vector of arboviruses, Ae. aegypti is also a convenient model for laboratory studies. A number of genetic loci related to the remarkable ability of this mosquito to transmit various pathogens were genetically mapped to the three linkage groups corresponding to the three individual chromosomes of the mosquito. However, the exact physical positions of the genetic loci and genomic sequences on the chromosomes were unknown. In this study, we developed maps for mitotic chromosomes of Ae. aegypti and localized 100 clones carrying major genetic markers, which were previously used for mapping genetic loci associated with the pathogens' transmission. Finally, linkage, chromosome, and genome maps of Ae. aegypti were integrated. Anchoring of the genomic sequences associated with genetic markers to the chromosomes of Ae. aegypti will help to identify candidate genes that might be utilized for developing advanced genome-based strategies for vector control.
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Affiliation(s)
- Vladimir A. Timoshevskiy
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - David W. Severson
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Becky S. deBruyn
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - William C. Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Igor V. Sharakhov
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Maria V. Sharakhova
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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Imaginal discs--a new source of chromosomes for genome mapping of the yellow fever mosquito Aedes aegypti. PLoS Negl Trop Dis 2011; 5:e1335. [PMID: 21991400 PMCID: PMC3186762 DOI: 10.1371/journal.pntd.0001335] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 08/12/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The mosquito Aedes aegypti is the primary global vector for dengue and yellow fever viruses. Sequencing of the Ae. aegypti genome has stimulated research in vector biology and insect genomics. However, the current genome assembly is highly fragmented with only ~31% of the genome being assigned to chromosomes. A lack of a reliable source of chromosomes for physical mapping has been a major impediment to improving the genome assembly of Ae. aegypti. METHODOLOGY/PRINCIPAL FINDINGS In this study we demonstrate the utility of mitotic chromosomes from imaginal discs of 4(th) instar larva for cytogenetic studies of Ae. aegypti. High numbers of mitotic divisions on each slide preparation, large sizes, and reproducible banding patterns of the individual chromosomes simplify cytogenetic procedures. Based on the banding structure of the chromosomes, we have developed idiograms for each of the three Ae. aegypti chromosomes and placed 10 BAC clones and a 18S rDNA probe to precise chromosomal positions. CONCLUSION The study identified imaginal discs of 4(th) instar larva as a superior source of mitotic chromosomes for Ae. aegypti. The proposed approach allows precise mapping of DNA probes to the chromosomal positions and can be utilized for obtaining a high-quality genome assembly of the yellow fever mosquito.
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Michalski ML, Erickson SM, Bartholomay LC, Christensen BM. Midgut barrier imparts selective resistance to filarial worm infection in Culex pipiens pipiens. PLoS Negl Trop Dis 2010; 4:e875. [PMID: 21072236 PMCID: PMC2970536 DOI: 10.1371/journal.pntd.0000875] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 10/06/2010] [Indexed: 11/30/2022] Open
Abstract
Mosquitoes in the Culex pipiens complex thrive in temperate and tropical regions worldwide, and serve as efficient vectors of Bancroftian lymphatic filariasis (LF) caused by Wuchereria bancrofti in Asia, Africa, the West Indies, South America, and Micronesia. However, members of this mosquito complex do not act as natural vectors for Brugian LF caused by Brugia malayi, or for the cat parasite B. pahangi, despite their presence in South Asia where these parasites are endemic. Previous work with the Iowa strain of Culex pipiens pipiens demonstrates that it is equally susceptible to W. bancrofti as is the natural Cx. p. pipiens vector in the Nile Delta, however it is refractory to infection with Brugia spp. Here we report that the infectivity barrier for Brugia spp. in Cx. p. pipiens is the mosquito midgut, which inflicts internal and lethal damage to ingested microfilariae. Following per os Brugia exposures, the prevalence of infection is significantly lower in Cx. p. pipiens compared to susceptible mosquito controls, and differs between parasite species with <50% and <5% of Cx. p. pipiens becoming infected with B. pahangi and B. malayi, respectively. When Brugia spp. mf were inoculated intrathoracically to bypass the midgut, larvae developed equally well as in controls, indicating that, beyond the midgut, Cx. p. pipiens is physiologically compatible with Brugia spp. Mf isolated from Cx. p. pipiens midguts exhibited compromised motility, and unlike mf derived from blood or isolated from the midguts of Ae. aegypti, failed to develop when inoculated intrathoracically into susceptible mosquitoes. Together these data strongly support the role of the midgut as the primary infection barrier for Brugia spp. in Cx. p. pipiens. Examination of parasites recovered from the Cx. p. pipiens midgut by vital staining, and those exsheathed with papain, suggest that the damage inflicted by the midgut is subcuticular and disrupts internal tissues. Microscopic studies of these worms reveal compromised motility and sharp bends in the body; and ultrastructurally the presence of many fluid or carbohydrate-filled vacuoles in the hypodermis, body wall, and nuclear column. Incubation of Brugia mf with Cx. p. pipiens midgut extracts produces similar internal damage phenotypes; indicating that the Cx. p. pipiens midgut factor(s) that damage mf in vivo are soluble and stable in physiological buffer, and inflict damage on mf in vitro. Culex pipiens complex mosquitoes transmit numerous diseases that affect humans and other animals. In many parts of the tropics they transmit Bancroftian lymphatic filariasis caused by the filarial nematode Wuchereria bancrofti. However, in parts of South Asia where Brugian lymphatic filariasis caused by Brugia spp. is endemic, this group of mosquitoes is present but does not play a role in transmission. The differential susceptibility of Cx. p. pipiens mosquitoes for Wuchereria but not Brugia species occurs as a result of the mosquito midgut environment. W. bancrofti larvae ingested with a bloodmeal can penetrate the Culex midgut, however Brugia larvae ingested by Cx. p. pipiens are unable to penetrate the midgut epithelium and die within the lumen. These observations suggest that toxic factor(s) exist within the lumen of the Cx. p. pipiens midgut that physically and lethally damage Brugia parasites. Understanding natural mechanisms of resistance to parasites in arthropod vectors is critical if we are to gain a complete understanding of the transmission dynamics and epidemiology of LF and other vector-borne diseases.
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Affiliation(s)
- Michelle L Michalski
- Department of Biology and Microbiology, University of Wisconsin-Oshkosh, Oshkosh, Wisconsin, United States of America.
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The Yin and Yang of linkage disequilibrium: mapping of genes and nucleotides conferring insecticide resistance in insect disease vectors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 627:71-83. [PMID: 18510015 DOI: 10.1007/978-0-387-78225-6_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Genetic technologies developed in the last 20 years have lead to novel and exciting methods to identify genes and specific nucleotides within genes that control phenotypes in field collected organisms. In this review we define and explain two of these methods: linkage disequilibrium (LD) mapping and quantitative trait nucleotide (QTN) mapping. The power to detect valid genotype-phenotype associations with LD or QTN mapping depends critically on the extent to which segregating sites in a genome assort independently. LD mapping depends on markers being in disequilibrium with the genes that condition expression of the phenotype. In contrast, QTN mapping depends critically upon most proximal loci being at equilibrium. We show that both patterns actually exist in the genome of Anapheles gambiae, the most important malaria vector in sub-Saharan Africa while segregating sites appear to be largely in equilibrium throughout the genome of Aedes aegypti, the vector of Dengue and Yellow fever flaviviruses. We discuss additional approaches that will be needed to identify genes and nucleotides that control phenotypes in field collected organisms, focusing specifically on ongoing studies of genes conferring resistance to insecticides.
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18
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Pothikasikorn J, Bangs MJ, Chareonviriyaphap T, Roongruangchai K, Roongruangchai J. Comparison of blood feeding response and infection of Aedes aegypti to Wuchereria bancrofti using animal membranes and direct host contact. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2007; 23:294-298. [PMID: 17939509 DOI: 10.2987/8756-971x(2007)23[294:cobfra]2.0.co;2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Comparison of an artificial, whole-blood membrane feeding procedure was performed by feeding Aedes aegypti (Liverpool strain) on the blood of patients infected with Wuchereria bancrofti microfilariae with the use of 3 types of membranes produced from chicken and mouse skin and swine intestine. Direct feeding of Ae. aegypti on the skin of infected human patients served as control. For all 3 types of membranes, mosquito survival, infection, and number of infective-stage larvae per mosquito did not differ significantly from the control. However, the blood feeding response between swine intestine layer (32%) compared to chicken skin (75.3%), mouse skin (70%), and direct feeding (84%) differed significantly. The response in direct feeding method was significantly higher than those in all membranes tested (F = 18.89; df = 3; P < 0.05) Chicken skin preparation was shown to be the preferred membrane for blood feeding Ae. aegypti and experimental infection with W. bancrofti.
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Affiliation(s)
- Jinrapa Pothikasikorn
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400 Thailand
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19
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Zhong D, Menge DM, Temu EA, Chen H, Yan G. Amplified fragment length polymorphism mapping of quantitative trait loci for malaria parasite susceptibility in the yellow fever mosquito Aedes aegypti. Genetics 2006; 173:1337-45. [PMID: 16624910 PMCID: PMC1526673 DOI: 10.1534/genetics.105.055178] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The yellow fever mosquito Aedes aegypti has been the subject of extensive genetic research due to its medical importance and the ease with which it can be manipulated in the laboratory. A molecular genetic linkage map was constructed using 148 amplified fragment length polymorphism (AFLP) and six single-strand conformation polymorphism (SSCP) markers. Eighteen AFLP primer combinations were used to genotype two reciprocal F2 segregating populations. Each primer combination generated an average of 8.2 AFLP markers eligible for linkage mapping. The length of the integrated map was 180.9 cM, giving an average marker resolution of 1.2 cM. Composite interval mapping revealed a total of six QTL significantly affecting Plasmodium susceptibility in the two reciprocal crosses of Ae. aegypti. Two common QTL on linkage group 2 were identified in both crosses that had similar effects on the phenotype, and four QTL were unique to each cross. In one cross, the four main QTL accounted for 64% of the total phenotypic variance, and digenic epistasis explained 11.8% of the variance. In the second cross, the four main QTL explained 66% of the variance, and digenic epistasis accounted for 16% of the variance. The actions of these QTL were either dominance or underdominance. Our results indicated that at least three new QTL were mapped on chromosomes 1 and 3. The polygenic nature of susceptibility to P. gallinaceum and epistasis are important factors for significant variation within or among mosquito strains. The new map provides additional information useful for further genetic investigation, such as identification of new genes and positional cloning.
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Affiliation(s)
- Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California, Irvine, California 92697, USA.
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20
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Anderson JR, Schneider JR, Grimstad PR, Severson DW. Quantitative genetics of vector competence for La Crosse virus and body size in Ochlerotatus hendersoni and Ochlerotatus triseriatus interspecific hybrids. Genetics 2005; 169:1529-39. [PMID: 15654112 PMCID: PMC1449537 DOI: 10.1534/genetics.104.033639] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Accepted: 12/07/2004] [Indexed: 11/18/2022] Open
Abstract
La Crosse virus is a leading cause of pediatric encephalitis in the United States. The mosquito Ochlerotatus triseriatus is an efficient vector for La Crosse virus, whereas the closely related O. hendersoni transmits only at very low rates. Quantitative trait loci (QTL) affecting the ability to orally transmit this virus and adult body size were identified in 164 F(2) female individuals from interspecific crosses of O. hendersoni females and O. triseriatus males using a combination of composite interval mapping (CIM), interval mapping (IM) for binary traits, and single-marker mapping. For oral transmission (OT), no genome locations exceeded the 95% experimentwise threshold for declaring a QTL using IM, but single-marker analysis identified four independent regions significantly associated with OT that we considered as tentative QTL. With two QTL, an increase in OT was associated with alleles from the refractory vector, O. hendersoni, and likely reflect epistatic interactions between genes that were uncovered by our interspecific crosses. For body size, two QTL were identified using CIM and a third tentative QTL was identified using single-marker analysis. The genome regions associated with body size also contain three QTL controlling OT, suggesting that these regions contain either single genes with pleiotropic effects or multiple linked genes independently determining each trait.
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Affiliation(s)
- Justin R Anderson
- Center for Tropical Disease Research and Training, Department of Biological Sciences, University of Notre Dame, Indiana 46556, USA
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21
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Carton Y, Nappi AJ, Poirie M. Genetics of anti-parasite resistance in invertebrates. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2005; 29:9-32. [PMID: 15325520 DOI: 10.1016/j.dci.2004.05.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 04/21/2004] [Accepted: 05/12/2004] [Indexed: 05/24/2023]
Abstract
This review summarizes and compares available data on genetic and molecular aspects of resistance in four well-described invertebrate host-parasite systems: snail-schistosome, mosquito-malaria, mosquito-filarial worm, and Drosophila-wasp associations. It underlies that the major components of the immune reaction, such as hemocyte proliferation and/or activation, and production of cytotoxic radicals are common to invertebrate hosts. Identifying genes responsible for naturally occurring resistance will then be helpful to understand the mechanisms of invertebrate immune defenses and to determine how virulence factors are used by parasites to overcome host resistance. Based on these four well-studied models, invertebrate resistance appears as generally determined by one major locus or a few loci, displaying at least partial dominance. Interestingly, specificity of resistance is highly variable and would involve processes other than simple recognition mechanisms. Finally, resistance was shown to be generally costly but is nevertheless observed at high frequencies in many natural populations, suggesting a high potential for host parasite coevolution.
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Affiliation(s)
- Y Carton
- Laboratoire Populations, Génétique et Evolution, CNRS, 91198 Gif, Yvette, France.
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22
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Affiliation(s)
- Bruce M Christensen
- Department of Animal Health and Biomedical Sciences, School of Veterinary Medicine, 1656 Linden Drive, University of Wisconsin-Madison, Madison, Wisconsin 53706-1520, USA.
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Severson DW, Knudson DL, Soares MB, Loftus BJ. Aedes aegypti genomics. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2004; 34:715-721. [PMID: 15242713 DOI: 10.1016/j.ibmb.2004.03.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Accepted: 03/18/2004] [Indexed: 05/24/2023]
Abstract
The mosquito, Aedes aegypti, is the primary, worldwide arthropod vector for the yellow fever and dengue viruses. As it is also one of the most tractable mosquito species for laboratory studies, it has been and remains one of the most intensively studied arthropod species. This has resulted in the development of detailed genetic and physical maps for Ae. aegypti and considerable insight into its genome organization. The research community is well-advanced in developing important molecular tools that will facilitate a whole genome sequencing effort. This includes generation of BAC clone end sequences, physical mapping of selected BAC clones and generation of EST sequences. Whole genome sequence information for Ae. aegypti will provide important insight into mosquito chromosome evolution and allow for the identification of genes and gene function. These functions may be common to all mosquitoes or perhaps unique to individual species, possibly specific to host-seeking and blood-feeding behaviors, as well as the innate immune response to pathogens encountered during blood-feeding. This information will be invaluable to the global effort to develop novel strategies for preventing arthropod-borne disease transmission.
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Affiliation(s)
- David W Severson
- Department of Biological Sciences, Center for Tropical Disease Research and Training, University of Notre Dame, Notre Dame, IN 46556, USA.
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Graham DH, Holmes JL, Beaty BJ, Black WC. Quantitative trait loci conditioning transovarial transmission of La Crosse virus in the eastern treehole mosquito, Ochlerotatus triseriatus. INSECT MOLECULAR BIOLOGY 2003; 12:307-318. [PMID: 12864911 DOI: 10.1046/j.1365-2583.2003.00412.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Quantitative trait loci (QTL) affecting the ability of the Eastern treehole mosquito, Ochlerotatus triseriatus, to transovarially transmit (TOT) La Crosse virus (LAC) were mapped in an F1 intercross. The Holmen strain of O. triseriatus, previously selected for TOT refractoriness, was crossed to the AIDL strain that had been selected for TOT permissiveness. In P1 and F1 parents and 49 F2 individuals, regions of 10 cDNA loci were analysed with single strand conformation polymorphism (SSCP) analysis to identify and orientate linkage groups. Genotypes were also scored at fifty-six random amplified polymorphic DNA (RAPD)-SSCP loci. Twenty-eight F2 offspring were individually analysed for TOT. Three QTL for TOT were detected with standard interval mapping on chromosomes II and III. Alleles at the three loci contributed additively towards determining the overall TOT rate and cumulatively accounted for approximately 53% of the phenotypic variance in TOT.
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Affiliation(s)
- Douglas H Graham
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1677, USA
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25
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Luna C, Hoa NT, Zhang J, Kanzok SM, Brown SE, Imler JL, Knudson DL, Zheng L. Characterization of three Toll-like genes from mosquito Aedes aegypti. INSECT MOLECULAR BIOLOGY 2003; 12:67-74. [PMID: 12542637 DOI: 10.1046/j.1365-2583.2003.00388.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Three Toll-related genes (AeToll1A, AeToll1B and AeToll5) were cloned and characterized from the yellow fever vector mosquito, Aedes aegypti. All three genes exhibited high levels of amino acid sequence similarity with Drosophila melanogaster (Dm)Toll1 and DmTehao (Toll5). AeToll1A and AeToll1B are 1124 and 1076 amino acid residues long, respectively. Both contain a carboxyl extension downstream of the Toll/interleukin-1 receptor (TIR) domain. AeToll5 is 1007 residues long and, like DmTehao, lacks the carboxyl terminal extension. Expression of these three genes was examined throughout development and after immune challenge. Both AeToll1A and AeToll5, like their Drosophila counterparts, activate transcription of drosomycin promoter in both Aedes and Drosophila cell lines. Deletion of the carboxyl extension of AeToll1A did not result in a further elevated level of the antifungal response. The intracellular signalling process appears to be species specific based on two observations. (1) DmToll is completely inactive in an Aedes cell line, suggesting a higher specificity requirement for DmToll in the intracellular signalling process. (2) Only one of three amino acid residues essential for DmToll function is required for AeToll1A function.
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Affiliation(s)
- C Luna
- Yale University School of Medicine, Epidemiology and Public Health, New Haven, CT 06520, USA
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Knudson DL, Brown SE, Severson DW. Culicine genomics. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2002; 32:1193-1197. [PMID: 12225910 DOI: 10.1016/s0965-1748(02)00082-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- Dennis L Knudson
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523, USA.
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Severson DW, Meece JK, Lovin DD, Saha G, Morlais I. Linkage map organization of expressed sequence tags and sequence tagged sites in the mosquito, Aedes aegypti. INSECT MOLECULAR BIOLOGY 2002; 11:371-378. [PMID: 12144703 DOI: 10.1046/j.1365-2583.2002.00347.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A composite genetic linkage map for the yellow fever mosquito Aedes aegypti was constructed based on restriction fragment length polymorphism (RFLP), single nucleotide polymorphism (SNP) and single strand conformation polymorphism (SSCP) markers. The map consists of 146 marker loci distributed across 205 cM, and includes several morphological mutant marker loci. Most of the genetic markers are derived from random cDNAs or Ae. aegypti genes of known function. A number of markers are derived from random genomic DNAs, including several cloned RAPD-PCR fragments, and also several cDNAs from Drosophila melanogaster. Most of the random cDNAs (80.2%) have high BlastX sequence identities to known genes, with the majority of matches to genes from D. melanogaster. Access to sequence data for all markers will facilitate their continued development for use in high-throughput SNP marker analyses and also provides additional physical anchor points for an anticipated genome sequencing effort.
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Affiliation(s)
- D W Severson
- Center for Tropical Disease Research and Training, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
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Black WC, Bennett KE, Gorrochótegui-Escalante N, Barillas-Mury CV, Fernández-Salas I, de Lourdes Muñoz M, Farfán-Alé JA, Olson KE, Beaty BJ. Flavivirus susceptibility in Aedes aegypti. Arch Med Res 2002; 33:379-88. [PMID: 12234528 DOI: 10.1016/s0188-4409(02)00373-9] [Citation(s) in RCA: 238] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti.
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Affiliation(s)
- William C Black
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
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Abstract
Genome projects and associated technologies are now being established for mosquito species that are vectors of human disease. The recent announcement of an award by the National Institute of Allergy and Infectious Diseases (NIAID) to Celera Genomics to sequence the Anopheles gambiae genome will further accelerate the completion of the sequencing of this genome. Completion of the An. gambiae sequence will mean that the genomes of all three organisms involved in the transmission of falciparum malaria--the mosquito, the parasite, and the human--will have been sequenced. This will greatly facilitate the identification of genes and pathways involved in the transmission of malaria. The recent genetic transformation of An. gambiae with the piggyBac transposable element and the transformation of another important malarial vector, Anopheles stephensi using the Minos element, now provide researchers with powerful tools with which to genetically manipulate these medically important vector species. Here we review the recent progress made in the extension of contemporary tools of modern genetics and genomics into these medically important insects.
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Affiliation(s)
- Peter W Atkinson
- Department of Entomology, University of California, Riverside, California 92521, USA.
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Brown SE, Severson DW, Smith LA, Knudson DL. Integration of the Aedes aegypti mosquito genetic linkage and physical maps. Genetics 2001; 157:1299-305. [PMID: 11238414 PMCID: PMC1461557 DOI: 10.1093/genetics/157.3.1299] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Two approaches were used to correlate the Aedes aegypti genetic linkage map to the physical map. STS markers were developed for previously mapped RFLP-based genetic markers so that large genomic clones from cosmid libraries could be found and placed to the metaphase chromosome physical maps using standard FISH methods. Eight cosmids were identified that contained eight RFLP marker sequences, and these cosmids were located on the metaphase chromosomes. Twenty-one cDNAs were mapped directly to metaphase chromosomes using a FISH amplification procedure. The chromosome numbering schemes of the genetic linkage and physical maps corresponded directly and the orientations of the genetic linkage maps for chromosomes 2 and 3 were inverted relative to the physical maps. While the chromosome 2 linkage map represented essentially 100% of chromosome 2, approximately 65% of the chromosome 1 linkage map mapped to only 36% of the short p-arm and 83% of the chromosome 3 physical map contained the complete genetic linkage map. Since the genetic linkage map is a RFLP cDNA-based map, these data also provide a minimal estimate for the size of the euchromatic regions. The implications of these findings on positional cloning in A. aegypti are discussed.
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Affiliation(s)
- S E Brown
- Department of Bioagricultural Sciences and Pest Management, College of Agricultural Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
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Severson DW, Brown SE, Knudson DL. Genetic and physical mapping in mosquitoes: molecular approaches. ANNUAL REVIEW OF ENTOMOLOGY 2001; 46:183-219. [PMID: 11112168 DOI: 10.1146/annurev.ento.46.1.183] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The genetic background of individual mosquito species and populations within those species influences the transmission of mosquito-borne pathogens to humans. Technical advances in contemporary genomics are contributing significantly to the detailed genetic analysis of this mosquito-pathogen interaction as well as all other aspects of mosquito biology, ecology, and evolution. A variety of DNA-based marker types are being used to develop genetic maps for a number of mosquito species. Complex phenotypic traits such as vector competence are being dissected into their discrete genetic components, with the intention of eventually using this information to develop new methods to prevent disease transmission. Both genetic- and physical-mapping techniques are being used to define and compare genome architecture among and within mosquito species. The integration of genetic- and physical-map information is providing a sound framework for map-based positional cloning of target genes of interest. This review focuses on advances in genome-based analysis and their specific applications to mosquitoes.
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Affiliation(s)
- D W Severson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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Bosio CF, Fulton RE, Salasek ML, Beaty BJ, Black WC. Quantitative trait loci that control vector competence for dengue-2 virus in the mosquito Aedes aegypti. Genetics 2000; 156:687-98. [PMID: 11014816 PMCID: PMC1461298 DOI: 10.1093/genetics/156.2.687] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantitative trait loci (QTL) affecting the ability of the mosquito Aedes aegypti to become infected with dengue-2 virus were mapped in an F(1) intercross. Dengue-susceptible A. aegypti aegypti were crossed with dengue refractory A. aegypti formosus. F(2) offspring were analyzed for midgut infection and escape barriers. In P(1) and F(1) parents and in 207 F(2) individuals, regions of 14 cDNA loci were analyzed with single-strand conformation polymorphism analysis to identify and orient linkage groups with respect to chromosomes I-III. Genotypes were also scored at 57 RAPD-SSCP loci, 5 (TAG)(n) microsatellite loci, and 6 sequence-tagged RAPD loci. Dengue infection phenotypes were scored in 86 F(2) females. Two QTL for a midgut infection barrier were detected with standard and composite interval mapping on chromosomes II and III that accounted for approximately 30% of the phenotypic variance (sigma(2)(p)) in dengue infection and these accounted for 44 and 56%, respectively, of the overall genetic variance (sigma(2)(g)). QTL of minor effect were detected on chromosomes I and III, but these were not detected with composite interval mapping. Evidence for a QTL for midgut escape barrier was detected with standard interval mapping but not with composite interval mapping on chromosome III.
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Affiliation(s)
- C F Bosio
- Arthropod Borne and Infectious Diseases Laboratory, Department of Microbiology, Colorado State University, Fort Collins, Colorado 80523, USA
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Ranson H, Jensen B, Wang X, Prapanthadara L, Hemingway J, Collins FH. Genetic mapping of two loci affecting DDT resistance in the malaria vector Anopheles gambiae. INSECT MOLECULAR BIOLOGY 2000; 9:499-507. [PMID: 11029668 DOI: 10.1046/j.1365-2583.2000.00214.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Resistance to the insecticide DDT in the mosquito vectors of malaria has severely hampered efforts to control this disease and has contributed to the increase in prevalence of malaria cases seen in recent years. Over 90% of the 300-500 million annual cases of malaria occur in Africa, where the major vector is Anopheles gambiae. DDT resistance in the ZAN/U strain of An. gambiae is associated with an increased metabolism of the insecticide, catalysed by members of the glutathione S-transferase (GST) enzyme family, but the molecular mechanism underlying this metabolic resistance is not known. Genetic crosses show that resistance is autosomal and semidominant. We have used microsatellite markers to identify two quantitative trait loci (QTL), which together explain over 50% of the variance in susceptibility to DDT in the ZAN/U strain of An. gambiae. The first locus, rtd1, is on chromosome 3 between markers H341 and H88 and has a recessive effect with respect to susceptibility. The second locus, rtd2 is on chromosome 2L, close to marker H325 and has an additive genetic effect. The markers flanking these two QTL have been physically mapped to An. gambiae polytene chromosomes. They do not coincide with any of the GST genes that have been cloned and mapped in this species. Characterization of these QTL will lead to a clearer understanding of the mechanisms of metabolic resistance to DDT.
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Affiliation(s)
- H Ranson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
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Abstract
Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality.
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Affiliation(s)
- B T Beerntsen
- Department of Molecular Biology & Biochemistry, University of California, Irvine, California 92697, USA
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Brown SE, Wood SH, Knudson DL. Vertebrate exon trapping methods: implications for transcript mapping with mosquito DNA. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1999; 29:643-651. [PMID: 10436938 DOI: 10.1016/s0965-1748(99)00042-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Exon trapping methods have played an important role in the development of transcript maps. In one in vivo vertebrate method, exons in a genomic DNA clone are transcribed, and they are recovered without any a priori information on the nature of the expressed transcript. The only requirement is that the genomic DNA clone contains exons separated by intervening introns that are removed by splicing during mRNA transcription and that the splice donor and acceptor site sequences follow those used by vertebrates. It is not known whether invertebrate splice donor and acceptor sites from genes that contain short introns will be processed correctly using an in vivo vertebrate exon trapping method. In this report, an analysis of mosquito splice sites using software designed to identify exons in genomic DNA sequence suggested that the vertebrate exon trapping method could recognize mosquito introns and exons. When a mosquito genomic DNA clone containing the D7 gene was tested experimentally, this method failed to recognize and process small introns (< 63 bp) faithfully. In spite of this failure, exons and exon fragments were recovered. The implications of these findings and their application to map-based positional cloning in mosquito genomics is discussed.
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Affiliation(s)
- S E Brown
- Department of Bioagricultural Sciences and Pest Management, College of Agricultural Sciences, Colorado State University, Fort Collins 80523, USA
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Lowenberger CA, Smartt CT, Bulet P, Ferdig MT, Severson DW, Hoffmann JA, Christensen BM. Insect immunity: molecular cloning, expression, and characterization of cDNAs and genomic DNA encoding three isoforms of insect defensin in Aedes aegypti. INSECT MOLECULAR BIOLOGY 1999; 8:107-118. [PMID: 9927179 DOI: 10.1046/j.1365-2583.1999.810107.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Aedes aegypti were immune activated by injection with bacteria, and the expression of insect defensins was measured over time. Northern analyses indicated that defensin transcriptional activity continued for at least 21 days after bacterial injection, and up to 10 days after saline inoculation. Mature defensin levels in the haemolymph reached approximately 45 microM at 24 h post inoculation. cDNAs encoding the preprodefensins of three previously described mature Ae. aegypti defensins were amplified by PCR, cloned and sequenced. Genomic clones were amplified using primers designed against the cDNA sequence. Sequence comparison indicates that there is significant inter- and intra-isoform variability in the signal peptide and prodefensin sequences of defensin genes. Preprodefensin sequences of isoforms A and B are very similar, consisting of a signal peptide region of twenty amino acids, a prodefensin region of thirty-eight amino acids and a forty amino acid mature peptide domain. The sequence encoding isoform C is significantly different, comprising a signal peptide region of twenty-three amino acids, a prodefensin region of thirty-six amino acids, and the mature protein domain of forty amino acids. Analysis of the genomic clones of each isoform revealed one intron spatially conserved in the prodefensin region of all sequences. The intron in isoforms A and B is 64 nt long, and except for a 4 nt substitution in one clone, these intron sequences are identical. The intron in isoform C is 76 nt long and does not share significant identity with the intron sequences of isoforms A or B. The defensin gene mapped to chromosome 3, between two known loci, blt and LF168.
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Affiliation(s)
- C A Lowenberger
- Animal Health and Biomedical Sciences, University of Wisconsin-Madison, 53706, USA.
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Yan G, Chadee DD, Severson DW. Evidence for genetic hitchhiking effect associated with insecticide resistance in Aedes aegypti. Genetics 1998; 148:793-800. [PMID: 9504925 PMCID: PMC1459830 DOI: 10.1093/genetics/148.2.793] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Information on genetic variation within and between populations is critical for understanding the evolutionary history of mosquito populations and disease epidemiology. Previous studies with Drosophila suggest that genetic variation of selectively neutral loci in a large fraction of genome may be constrained by fixation of advantageous mutations associated with hitchhiking effect. This study examined restriction fragment length polymorphisms of four natural Aedes aegypti mosquito populations from Trinidad and Tobago, at 16 loci. These populations have been subjected to organophosphate (OP) insecticide treatments for more than two decades, while dichlor-diphenyltrichlor (DDT) was the insecticide of choice prior to this period. We predicted that genes closely linked to the OP target loci would exhibit reduced genetic variation as a result of the hitchhiking effect associated with intensive OP insecticide selection. We also predicted that genetic variability of the genes conferring resistance to DDT and loci near the target site would be similar to other unlinked loci. As predicted, reduced genetic variation was found for loci in the general chromosomal region of a putative OP target site, and these loci generally exhibited larger F(ST) values than other random loci. In contrast, the gene conferring resistance to DDT and its linked loci show polymorphisms and genetic differentiation similar to other random loci. The reduced genetic variability and apparent gene deletion in some regions of chromosome 1 likely reflect the hitchhiking effect associated with OP insecticide selection.
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Affiliation(s)
- G Yan
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison 53706, USA.
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Ferdig MT, Taft AS, Severson DW, Christensen BM. Development of a comparative genetic linkage map for Armigeres subalbatus using Aedes aegypti RFLP markers. Genome Res 1998; 8:41-7. [PMID: 9445486 DOI: 10.1101/gr.8.1.41] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
One of the causative agents of lympahtic filariasis is the nematode parasite Brugia malayi that requires a competent mosquito vector for its development and transmission. Armigeres subalbatus mosquitoes rapidly destroy invading B. malayi microfilariae via a defense response known as melanotic encapsulation. We have constructed a genetic linkage map for this mosquito species using RFLP markers from Aedes aegypti. This heterologous approach was possible because of the conserved nature of the coding sequences used as markers and provided an experimental framework to evaluate the hypothesis that linkage and gene order are conserved between these mosquito species. Of the 56 Ae. aegypti markers tested, 77% hybridize to genomic DNA digests of Ar. subalbatus under stringent conditions, with 53% of these demonstrating strain-specific polymorphisms. Twenty-six Ae. aegypti markers have been mapped using an F2- segregating Ar. subalbatus population derived from a cross of strains originating in Japan and Malaysia. Linear order of these marker loci is highly conserved between the two species. Only 1 of these markers, LF92, was not linked in the manner predicted by the Ae. aegypti map. In addition, the autosomal sex-determination locus that occurs in linkage group 1 in Ae. aegypti resides in group 3 in Ar. subalbatus. The Ar. subalbatus map provides a basic genetic context that can be utilized in further genetic studies to clarify the genetic basis of parasite resistance in this mosquito and is a necessary precursor to the identification of genome regions that carry genes that determine the encapsulation phenotype. [The composite map and sequence database information for Ae. aegypti markers can be retrieved directly from the Ae. aegypti Genome Database through the World Wide Web: http://klab.agsci.colostate.edu.]
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Affiliation(s)
- M T Ferdig
- University of Wisconsin-Madison, Department of Animal Health and Biomedical Sciences, Madison, Wisconsin 53706-1581, USA
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40
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Zheng L, Cornel AJ, Wang R, Erfle H, Voss H, Ansorge W, Kafatos FC, Collins FH. Quantitative trait loci for refractoriness of Anopheles gambiae to Plasmodium cynomolgi B. Science 1997; 276:425-8. [PMID: 9103203 DOI: 10.1126/science.276.5311.425] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The severity of the malaria pandemic in the tropics is aggravated by the ongoing spread of parasite resistance to antimalarial drugs and mosquito resistance to insecticides. A strain of Anopheles gambiae, normally a major vector for human malaria in Africa, can encapsulate and kill the malaria parasites within a melanin-rich capsule in the mosquito midgut. Genetic mapping revealed one major and two minor quantitative trait loci (QTLs) for this encapsulation reaction. Understanding such antiparasite mechanisms in mosquitoes may lead to new strategies for malaria control.
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Affiliation(s)
- L Zheng
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Disease Control and Prevention, 4770 Buford Hi
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41
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Dimopoulos G, Zheng L, Kumar V, della Torre A, Kafatos FC, Louis C. Integrated genetic map of Anopheles gambiae: use of RAPD polymorphisms for genetic, cytogenetic and STS landmarks. Genetics 1996; 143:953-60. [PMID: 8725241 PMCID: PMC1207351 DOI: 10.1093/genetics/143.2.953] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Randomly amplified polymorphic DNA (RAPD) markers have been integrated in the genetic and cytogenetic maps of the malaria vector mosquito, Anopheles gambiae. Fifteen of these markers were mapped by recombination, relative to microsatellite markers that had been mapped previously. Thirty-four gel-purified RAPD bands were cloned and sequenced, generating sequence tagged sites (STSs) that can be used as entry points to the A. gambiae genome. Thirty one of these STSs were localized on nurse cell polytene chromosomes through their unique hybridization signal in in situ hybridization experiments. Five STSs map close to the breakpoints of polymorphic inversions, which are notable features of the Anopheles genome. The usefulness and limitations of this integrated mosquito map are discussed.
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Affiliation(s)
- G Dimopoulos
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
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Severson DW, Mori A, Kassner VA, Christensen BM. Comparative linkage maps for the mosquitoes, Aedes albopictus and Ae. aegypti, based on common RFLP loci. INSECT MOLECULAR BIOLOGY 1995; 4:41-45. [PMID: 7742975 DOI: 10.1111/j.1365-2583.1995.tb00006.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Aedes albopictus and Aedes aegypti are members of the mosquito family Culicidae and share a haploid chromosome complement of three. Although a genetic linkage map based on restriction fragment length polymorphism (RFLP), markers exists for Ae. aegypti, the extent of synteny and linkage order conservation between the two species was unknown. A comparative linkage map for Ae. albopictus was constructed based mainly on cDNA clones from Ae. aegypti. Nearly all Ae. aegypti probes hybridized to Ae. albopictus DNA at high stringency. For eighteen RFLP markers tested, the linkage group and linear order appears to be identical for the two species. 78% of the loci tested exhibited significant deviations from the expected segregation ratio in at least one of the test crosses. An excess of heterozygote genotypes was recovered with most loci. This probably reflects the effects of lethal loci on survival of F2 progeny homozygous for the parental genotypes. These results demonstrate that comparative linkage maps based on common DNA markers provide a basis for rapidly developing linkage maps for various mosquito species, and the opportunity to examine the significance and function of orthologous quantitative trait loci associated with mosquito vector competence for disease transmission.
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Affiliation(s)
- D W Severson
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison 53706, USA
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Severson DW. Applications of molecular marker analysis to mosquito vector competence. ACTA ACUST UNITED AC 1994; 10:336-40. [PMID: 15275410 DOI: 10.1016/0169-4758(94)90243-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A rapidly expanding cadre of molecular biology techniques is being developed for human and plant genetics, including development of the technology to identify large numbers of genetic markers and to evaluate these markers relative to phenotypic observations. In this review, David Severson discusses applications of these techniques for the analysis of mosquito vector competence.
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Affiliation(s)
- D W Severson
- Department of Animal Health and Biomedical Sciences, 1655 Linden Drive, University of Madison, Madison, WI 53706, USA
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