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Antonio-Nkondjio C, Ndo C, Njiokou F, Bigoga JD, Awono-Ambene P, Etang J, Ekobo AS, Wondji CS. Review of malaria situation in Cameroon: technical viewpoint on challenges and prospects for disease elimination. Parasit Vectors 2019; 12:501. [PMID: 31655608 PMCID: PMC6815446 DOI: 10.1186/s13071-019-3753-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 10/18/2019] [Indexed: 11/30/2022] Open
Abstract
Malaria still has a devastating impact on public health and welfare in Cameroon. Despite the increasing number of studies conducted on disease prevalence, transmission patterns or treatment, there are to date, not enough studies summarising findings from previous works in order to identify gaps in knowledge and areas of interest where further evidence is needed to drive malaria elimination efforts. The present study seeks to address these gaps by providing a review of studies conducted so far on malaria in Cameroon since the 1940s to date. Over 250 scientific publications were consulted for this purpose. Although there has been increased scale-up of vector control interventions which significantly reduced the morbidity and mortality to malaria across the country from a prevalence of 41% of the population reporting at least one malaria case episode in 2000 to a prevalence of 24% in 2017, the situation is not yet under control. There is a high variability in disease endemicity between epidemiological settings with prevalence of Plasmodium parasitaemia varying from 7 to 85% in children aged 6 months to 15 years after long-lasting insecticidal nets (LLINs) scale-up. Four species of Plasmodium have been recorded across the country: Plasmodium falciparum, P. malariae, P. ovale and P. vivax. Several primate-infecting Plasmodium spp. are also circulating in Cameroon. A decline of artemisinin-based combinations therapeutic efficacy from 97% in 2006 to 90% in 2016 have been reported. Several mutations in the P. falciparum chloroquine resistance (Pfcrt) and P. falciparum multidrug resistance 1 (Pfmdr1) genes conferring resistance to either 4-amino-quinoleine, mefloquine, halofanthrine and quinine have been documented. Mutations in the Pfdhfr and Pfdhps genes involved in sulfadoxine-pyrimethamine are also on the rise. No mutation associated with artemisinin resistance has been recorded. Sixteen anopheline species contribute to malaria parasite transmission with six recognized as major vectors: An. gambiae, An. coluzzii, An. arabiensis, An. funestus, An. nili and An. moucheti. Studies conducted so far, indicated rapid expansion of DDT, pyrethroid and carbamate resistance in An. gambiae, An. coluzzii, An. arabiensis and An. funestus threatening the performance of LLINs. This review highlights the complex situation of malaria in Cameroon and the need to urgently implement and reinforce integrated control strategies in different epidemiological settings, as part of the substantial efforts to consolidate gains and advance towards malaria elimination in the country.
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Affiliation(s)
- Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B. P.288 Yaoundé, Cameroun
- Centre for Research in Infectious Disease (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, UK
| | - Cyrille Ndo
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
- Centre for Research in Infectious Disease (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Flobert Njiokou
- Centre for Research in Infectious Disease (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Jude D. Bigoga
- Laboratory for Vector Biology and control, National Reference Unit for Vector Control, The Biotechnology Center, Nkolbisson-University of Yaounde I, P.O. Box 3851, Messa, Yaounde, Cameroon
- Department of Biochemistry, Faculty of Science, University of Yaounde I, Yaounde, Cameroon
| | - Parfait Awono-Ambene
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B. P.288 Yaoundé, Cameroun
| | - Josiane Etang
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B. P.288 Yaoundé, Cameroun
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
- Institute for Insect Biotechnology, Justus Liebig University Gießen, Winchester Str. 2, 35394 Gießen, Germany
| | - Albert Same Ekobo
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Charles S. Wondji
- Centre for Research in Infectious Disease (CRID), P.O. Box 13591, Yaoundé, Cameroon
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, UK
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The Development of Cytogenetic Maps for Malaria Mosquitoes. INSECTS 2018; 9:insects9030121. [PMID: 30227611 PMCID: PMC6164047 DOI: 10.3390/insects9030121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/13/2018] [Accepted: 09/13/2018] [Indexed: 11/20/2022]
Abstract
Anopheline mosquitoes are important vectors of human malaria. Next-generation sequencing opens new opportunities for studies of mosquito genomes to uncover the genetic basis of a Plasmodium transmission. Physical mapping of genome sequences to polytene chromosomes significantly improves reference assemblies. High-resolution cytogenetic maps are essential for anchoring genome sequences to chromosomes as well as for studying breakpoints of chromosome rearrangements and chromatin protein localization. Here we describe a detailed pipeline for the development of high-resolution cytogenetic maps using polytene chromosomes of malaria mosquitoes. We apply this workflow to the refinement of the cytogenetic map developed for Anopheles beklemishevi.
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Artemov GN, Velichevskaya AI, Bondarenko SM, Karagyan GH, Aghayan SA, Arakelyan MS, Stegniy VN, Sharakhov IV, Sharakhova MV. A standard photomap of the ovarian nurse cell chromosomes for the dominant malaria vector in Europe and Middle East Anopheles sacharovi. Malar J 2018; 17:276. [PMID: 30060747 PMCID: PMC6065146 DOI: 10.1186/s12936-018-2428-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/25/2018] [Indexed: 08/10/2023] Open
Abstract
Background Anopheles sacharovi is a dominant malaria vector species in South Europe and the Middle East which has a highly plastic behaviour at both adult and larval stages. Such plasticity has prevented this species from eradication by several anti-vector campaigns. The development of new genome-based strategies for vector control will benefit from genome sequencing and physical chromosome mapping of this mosquito. Although a cytogenetic photomap for chromosomes from salivary glands of An. sacharovi has been developed, no cytogenetic map suitable for physical genome mapping is available. Methods Mosquitoes for this study were collected at adult stage in animal shelters in Armenia. Polytene chromosome preparations were prepared from ovarian nurse cells. Fluorescent in situ hybridization (FISH) was performed using PCR amplified probes. Results This study constructed a high-quality standard photomap for polytene chromosomes from ovarian nurse cells of An. sacharovi. Following the previous nomenclature, chromosomes were sub-divided into 39 numbered and 119 lettered sub-divisions. Chromosomal landmarks for the chromosome recognition were described. Using FISH, 4 PCR-amplified genic probes were mapped to the chromosomes. The positions of the probes demonstrated gene order reshuffling between An. sacharovi and Anopheles atroparvus which has not been seen cytologically. In addition, this study described specific chromosomal landmarks that can be used for the cytotaxonomic diagnostics of An. sacharovi based on the banding pattern of its polytene chromosomes. Conclusions This study constructed a high-quality standard photomap for ovarian nurse cell chromosomes of An. sacharovi and validated its utility for physical genome mapping. Based on the map, cytotaxonomic features for identification of An. sacharovi have been described. The cytogenetic map constructed in this study will assist in creating a chromosome-based genome assembly for this mosquito and in developing cytotaxonomic tools for identification of other species from the Maculipennis group.
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Affiliation(s)
- Gleb N Artemov
- Laboratory of Ecology, Genetics and Environment Protection, Tomsk State University, Tomsk, Russia
| | - Alena I Velichevskaya
- Laboratory of Ecology, Genetics and Environment Protection, Tomsk State University, Tomsk, Russia
| | - Semen M Bondarenko
- Laboratory of Ecology, Genetics and Environment Protection, Tomsk State University, Tomsk, Russia
| | - Gayane H Karagyan
- Scientific Center of Zoology and Hydroecology, The National Academy of Sciences of the Republic of Armenia, Yerevan, Armenia
| | - Sargis A Aghayan
- Scientific Center of Zoology and Hydroecology, The National Academy of Sciences of the Republic of Armenia, Yerevan, Armenia.,Chair of Zoology, Yerevan State University, Yerevan, Armenia
| | | | - Vladimir N Stegniy
- Laboratory of Ecology, Genetics and Environment Protection, Tomsk State University, Tomsk, Russia
| | - Igor V Sharakhov
- Laboratory of Ecology, Genetics and Environment Protection, Tomsk State University, Tomsk, Russia. .,Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.
| | - Maria V Sharakhova
- Laboratory of Ecology, Genetics and Environment Protection, Tomsk State University, Tomsk, Russia. .,Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, VA, USA.
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A cytogenetic photomap from ovarian nurse cell polytene chromosome of Anopheles stephensi (Diptera: Culicidae): a comparative study. THE NUCLEUS 2018. [DOI: 10.1007/s13237-018-0241-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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5
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Artemov GN, Bondarenko SM, Naumenko AN, Stegniy VN, Sharakhova MV, Sharakhov IV. Partial-arm translocations in evolution of malaria mosquitoes revealed by high-coverage physical mapping of the Anopheles atroparvus genome. BMC Genomics 2018; 19:278. [PMID: 29688842 PMCID: PMC5914054 DOI: 10.1186/s12864-018-4663-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 04/12/2018] [Indexed: 02/06/2023] Open
Abstract
Background Malaria mosquitoes have had a remarkable stability in the number of chromosomes in their karyotype (2n = 6) during 100 million years of evolution. Moreover, autosomal arms were assumed to maintain their integrity even if their associations with each other changed via whole-arm translocations. Here we use high-coverage comparative physical genome mapping of three Anopheles species to test the extent of evolutionary conservation of chromosomal arms in malaria mosquitoes. Results In this study, we developed a physical genome map for Anopheles atroparvus, one of the dominant malaria vectors in Europe. Using fluorescence in situ hybridization (FISH) of DNA probes with the ovarian nurse cell polytene chromosomes and synteny comparison, we anchored 56 genomic scaffolds to the An. atroparvus chromosomes. The obtained physical map represents 89.6% of the An. atroparvus genome. This genome has the second highest mapping coverage among Anophelinae assemblies after An. albimanus, which has 98.2% of the genome assigned to its chromosomes. A comparison of the An. atroparvus, An. albimanus, and An. gambiae genomes identified partial-arm translocations between the autosomal arms that break down the integrity of chromosome elements in evolution affecting the structure of the genetic material in the pericentromeric regions. Unlike An. atroparvus and An. albimanus, all chromosome elements of An. gambiae are fully syntenic with chromosome elements of the putative ancestral Anopheles karyotype. We also detected nonrandom distribution of large conserved synteny blocks and confirmed a higher rate of inversion fixation in the X chromosome compared with autosomes. Conclusions Our study demonstrates the power of physical mapping for understanding the genome evolution in malaria mosquitoes. The results indicate that syntenic relationships among chromosome elements of Anopheles species have not been fully preserved because of multiple partial-arm translocations. Electronic supplementary material The online version of this article (10.1186/s12864-018-4663-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gleb N Artemov
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia
| | - Semen M Bondarenko
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia
| | - Anastasia N Naumenko
- Department of Entomology, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA, 24061, USA
| | - Vladimir N Stegniy
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia
| | - Maria V Sharakhova
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia. .,Department of Entomology, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA, 24061, USA.
| | - Igor V Sharakhov
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russia. .,Department of Entomology, Fralin Life Science Institute, Virginia Polytechnic Institute and State University, 360 West Campus Drive, Blacksburg, VA, 24061, USA.
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Artemov GN, Gordeev MI, Kokhanenko AA, Moskaev AV, Velichevskaya AI, Stegniy VN, Sharakhov IV, Sharakhova MV. A standard photomap of ovarian nurse cell chromosomes and inversion polymorphism in Anopheles beklemishevi. Parasit Vectors 2018; 11:211. [PMID: 29587834 PMCID: PMC5870207 DOI: 10.1186/s13071-018-2657-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/17/2018] [Indexed: 11/23/2022] Open
Abstract
Background Anopheles beklemishevi is a member of the Maculipennis group of malaria mosquitoes that has the most northern distribution among other members of the group. Although a cytogenetic map for the larval salivary gland chromosomes of this species has been developed, a high-quality standard cytogenetic photomap that enables genomics and population genetics studies of this mosquito at the adult stage is still lacking. Methods In this study, a cytogenetic map for the polytene chromosomes of An. beklemishevi from ovarian nurse cells was developed using high-resolution digital imaging from field collected mosquitoes. PCR-amplified DNA probes for fluorescence in situ hybridization (FISH) were designed based on the genome of An. atroparvus. The DNA probe obtained by microdissection procedures from the breakpoint region was labelled in a DOP-PCR reaction. Population analysis was performed on 371 specimens collected in 18 locations. Results We report the development of a high-quality standard photomap for the polytene chromosomes from ovarian nurse cells of An. beklemishevi. To confirm the suitability of the map for physical mapping, several PCR-amplified probes were mapped to the chromosomes of An. beklemishevi using FISH. In addition, we identified and mapped DNA probes to flanking regions of the breakpoints of two inversions on chromosome X of this species. Inversion polymorphism was determined in 13 geographically distant populations of An. beklemishevi. Four polymorphic inversions were detected. The positions of common chromosomal inversions were indicated on the map. Conclusions The study constructed a standard photomap for ovarian nurse cell chromosomes of An. beklemishevi and tested its suitability for physical genome mapping and population studies. Cytogenetic analysis determined inversion polymorphism in natural populations of An. beklemishevi related to this species’ adaptation. Electronic supplementary material The online version of this article (10.1186/s13071-018-2657-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gleb N Artemov
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Mikhail I Gordeev
- Department of General Biology and Ecology, Moscow Regional State University, Moscow, Russia
| | - Alina A Kokhanenko
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Anton V Moskaev
- Department of General Biology and Ecology, Moscow Regional State University, Moscow, Russia
| | - Alena I Velichevskaya
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Vladimir N Stegniy
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia
| | - Igor V Sharakhov
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia. .,Virginia Tech, Department of Entomology, Fralin Life Science Institute, Blacksburg, VA, USA.
| | - Maria V Sharakhova
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, Tomsk, Russia. .,Virginia Tech, Department of Entomology, Fralin Life Science Institute, Blacksburg, VA, USA.
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The Physical Genome Mapping of Anopheles albimanus Corrected Scaffold Misassemblies and Identified Interarm Rearrangements in Genus Anopheles. G3-GENES GENOMES GENETICS 2017; 7:155-164. [PMID: 27821634 PMCID: PMC5217105 DOI: 10.1534/g3.116.034959] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The genome of the Neotropical malaria vector Anopheles albimanus was sequenced as part of the 16 Anopheles Genomes Project published in 2015. The draft assembly of this species consisted of 204 scaffolds with an N50 scaffold size of 18.1 Mb and a total assembly size of 170.5 Mb. It was among the smallest genomes with the longest scaffolds in the 16 Anopheles species cluster, making An. albimanus the logical choice for anchoring the genome assembly to chromosomes. In this study, we developed a high-resolution cytogenetic photomap with completely straightened polytene chromosomes from the salivary glands of the mosquito larvae. Based on this photomap, we constructed a chromosome-based genome assembly using fluorescent in situ hybridization of PCR-amplified DNA probes. Our physical mapping, assisted by an ortholog-based bioinformatics approach, identified and corrected nine misassemblies in five large genomic scaffolds. Misassemblies mostly occurred in junctions between contigs. Our comparative analysis of scaffolds with the An. gambiae genome detected multiple genetic exchanges between pericentromeric regions of chromosomal arms caused by partial-arm translocations. The final map consists of 40 ordered genomic scaffolds and corrected fragments of misassembled scaffolds. The An. albimanus physical map comprises 98.2% of the total genome assembly and represents the most complete genome map among mosquito species. This study demonstrates that physical mapping is a powerful tool for correcting errors in draft genome assemblies and for creating chromosome-anchored reference genomes.
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Gariou-Papalexiou A, Giardini MC, Augustinos AA, Drosopoulou E, Lanzavecchia SB, Cladera JL, Caceres C, Bourtzis K, Mavragani-Tsipidou P, Zacharopoulou A. Cytogenetic Analysis of the South American Fruit Fly Anastrepha fraterculus (Diptera:Tephritidae) Species Complex: Construction of Detailed Photographic Polytene Chromosome Maps of the Argentinian Af. sp.1 Member. PLoS One 2016; 11:e0157192. [PMID: 27362546 PMCID: PMC4928812 DOI: 10.1371/journal.pone.0157192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/25/2016] [Indexed: 01/28/2023] Open
Abstract
Genetic and cytogenetic studies constitute a significant basis for understanding the biology of insect pests and the design and the construction of genetic tools for biological control strategies. Anastrepha fraterculus is an important pest of the Tephritidae family. It is distributed from southern Texas through eastern Mexico, Central America and South America causing significant crop damage and economic losses. Currently it is considered as a species complex; until now seven members have been described based on multidisciplinary approaches. Here we report the cytogenetic analysis of an Argentinian population characterized as Af. sp.1 member of the Anastrepha fraterculus species complex. The mitotic karyotype and the first detailed photographic maps of the salivary gland polytene chromosomes are presented. The mitotic metaphase complement consists of six (6) pairs of chromosomes, including one pair of heteromorphic sex chromosomes, with the male being the heterogametic sex. The analysis of the salivary gland polytene complement shows a total number of five long chromosomes that correspond to the five autosomes of the mitotic karyotype and a heterochromatic network corresponding to the sex chromosomes. Comparison of the polytene chromosome maps between this species and Anastrepha ludens shows significant similarity. The polytene maps presented here are suitable for cytogenetic studies that could shed light on the species limits within this species complex and support the development of genetic tools for sterile insect technique (SIT) applications.
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Affiliation(s)
| | - María Cecilia Giardini
- Instituto de Genética EA Favret, Instituto Nacional Tecnología Agropecuaria, Hurlingham, Provincia de Buenos Aires, Argentina
| | - Antonios A. Augustinos
- Biology Department, University of Patras, Patras, Greece
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria
| | - Elena Drosopoulou
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Silvia B. Lanzavecchia
- Instituto de Genética EA Favret, Instituto Nacional Tecnología Agropecuaria, Hurlingham, Provincia de Buenos Aires, Argentina
| | - Jorge L. Cladera
- Instituto de Genética EA Favret, Instituto Nacional Tecnología Agropecuaria, Hurlingham, Provincia de Buenos Aires, Argentina
| | - Carlos Caceres
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria
| | - Penelope Mavragani-Tsipidou
- Department of Genetics, Development and Molecular Biology, School of Biology, Faculty of Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Artemov GN, Sharakhova MV, Naumenko AN, Karagodin DA, Baricheva EM, Stegniy VN, Sharakhov IV. A standard photomap of ovarian nurse cell chromosomes in the European malaria vector Anopheles atroparvus. MEDICAL AND VETERINARY ENTOMOLOGY 2015; 29:230-237. [PMID: 25776224 PMCID: PMC4515173 DOI: 10.1111/mve.12113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/20/2014] [Accepted: 06/04/2014] [Indexed: 06/04/2023]
Abstract
Anopheles atroparvus (Diptera: Culicidae) is one of the main malaria vectors of the Maculipennis group in Europe. Cytogenetic analysis based on salivary gland chromosomes has been used in taxonomic and population genetic studies of mosquitoes from this group. However, a high-resolution cytogenetic map that could be used in physical genome mapping in An. atroparvus is still lacking. In the present study, a high-quality photomap of the polytene chromosomes from ovarian nurse cells of An. atroparvus was developed. Using fluorescent in situ hybridization, 10 genes from the five largest genomic supercontigs on the polytene chromosome were localized and 28% of the genome was anchored to the cytogenetic map. The study established chromosome arm homology between An. atroparvus and the major African malaria vector Anopheles gambiae, suggesting a whole-arm translocation between autosomes of these two species. The standard photomap constructed for ovarian nurse cell chromosomes of An. atroparvus will be useful for routine physical mapping. This map will assist in the development of a fine-scale chromosome-based genome assembly for this species and will also facilitate comparative and evolutionary genomics studies in the genus Anopheles.
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Affiliation(s)
- Gleb N. Artemov
- Tomsk State University, Institute of Biology and Biophysics, Tomsk, Russia
| | - Maria V. Sharakhova
- Tomsk State University, Institute of Biology and Biophysics, Tomsk, Russia
- Virginia Tech, Department of Entomology, Fralin Life Science Institute, Blacksburg, VA, USA
| | - Anastasia N. Naumenko
- Virginia Tech, Department of Entomology, Fralin Life Science Institute, Blacksburg, VA, USA
| | | | | | | | - Igor V. Sharakhov
- Virginia Tech, Department of Entomology, Fralin Life Science Institute, Blacksburg, VA, USA
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Sharakhova MV, Antonio-Nkondjio C, Xia A, Ndo C, Awono-Ambene P, Simard F, Sharakhov IV. Polymorphic chromosomal inversions in Anopheles moucheti, a major malaria vector in Central Africa. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28:337-340. [PMID: 24192050 PMCID: PMC4010561 DOI: 10.1111/mve.12037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/29/2013] [Accepted: 09/09/2013] [Indexed: 06/02/2023]
Abstract
Anopheles moucheti Evans (Diptera: Culicidae) is a major vector of malaria in forested areas of Central Africa. However, few genetic tools are available for this species. The present study represents the first attempt to characterize chromosomes in An. moucheti females collected in Cameroon. Ovarian nurse cells contained polytene chromosomes, which were suitable for standard cytogenetic applications. The presence of three polymorphic chromosomal inversions in An. moucheti was revealed. Two of these inversions were located on the 2R chromosome arm. The homology between the 2R chromosome arms of An. moucheti and Anopheles gambiae Giles was established by fluorescent in situ hybridization of six An. gambiae genic sequences. Mapping of the probes on chromosomes of An. moucheti detected substantial gene order reshuffling between the two species. The presence of polytene chromosomes and polymorphic inversions in An. moucheti provides a new basis for further population genetic, taxonomic and ecological studies of this neglected malaria vector.
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Affiliation(s)
- Maria V. Sharakhova
- Department of Entomology, 203 Fralin Life Science Institute, MC 0346, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Ai Xia
- Department of Entomology, 203 Fralin Life Science Institute, MC 0346, Virginia Tech, Blacksburg, VA 24061, USA
| | - Cyrille Ndo
- Malaria Research Laboratory, OCEAC, PO Box 288, Yaoundé, Cameroon
- MIVEGEC (UMR IRD224-CNRS5290-UM1-UM2), Institut de Recherche pour le Développement (IRD), BP 64501, 34394, Montpellier, Cedex 5, France
- Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | | | - Frederic Simard
- MIVEGEC (UMR IRD224-CNRS5290-UM1-UM2), Institut de Recherche pour le Développement (IRD), BP 64501, 34394, Montpellier, Cedex 5, France
| | - Igor V. Sharakhov
- Department of Entomology, 203 Fralin Life Science Institute, MC 0346, Virginia Tech, Blacksburg, VA 24061, USA
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Kamali M, Marek PE, Peery A, Antonio-Nkondjio C, Ndo C, Tu Z, Simard F, Sharakhov IV. Multigene phylogenetics reveals temporal diversification of major African malaria vectors. PLoS One 2014; 9:e93580. [PMID: 24705448 PMCID: PMC3976319 DOI: 10.1371/journal.pone.0093580] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 03/05/2014] [Indexed: 12/21/2022] Open
Abstract
The major vectors of malaria in sub-Saharan Africa belong to subgenus Cellia. Yet, phylogenetic relationships and temporal diversification among African mosquito species have not been unambiguously determined. Knowledge about vector evolutionary history is crucial for correct interpretation of genetic changes identified through comparative genomics analyses. In this study, we estimated a molecular phylogeny using 49 gene sequences for the African malaria vectors An. gambiae, An. funestus, An. nili, the Asian malaria mosquito An. stephensi, and the outgroup species Culex quinquefasciatus and Aedes aegypti. To infer the phylogeny, we identified orthologous sequences uniformly distributed approximately every 5 Mb in the five chromosomal arms. The sequences were aligned and the phylogenetic trees were inferred using maximum likelihood and neighbor-joining methods. Bayesian molecular dating using a relaxed log normal model was used to infer divergence times. Trees from individual genes agreed with each other, placing An. nili as a basal clade that diversified from the studied malaria mosquito species 47.6 million years ago (mya). Other African malaria vectors originated more recently, and independently acquired traits related to vectorial capacity. The lineage leading to An. gambiae diverged 30.4 mya, while the African vector An. funestus and the Asian vector An. stephensi were the most closely related sister taxa that split 20.8 mya. These results were supported by consistently high bootstrap values in concatenated phylogenetic trees generated individually for each chromosomal arm. Genome-wide multigene phylogenetic analysis is a useful approach for discerning historic relationships among malaria vectors, providing a framework for the correct interpretation of genomic changes across species, and comprehending the evolutionary origins of this ubiquitous and deadly insect-borne disease.
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Affiliation(s)
- Maryam Kamali
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Paul E Marek
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Ashley Peery
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | | | - Cyrille Ndo
- Malaria Research Laboratory, OCEAC, Yaounde, Cameroon; MIVEGEC (UMR IRD224-CNRS5290-UM1-UM2), Institut de Recherche pour le Développement (IRD), Montpellier, France; Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Zhijian Tu
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Frederic Simard
- MIVEGEC (UMR IRD224-CNRS5290-UM1-UM2), Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
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Sharakhova MV, Peery A, Antonio-Nkondjio C, Xia A, Ndo C, Awono-Ambene P, Simard F, Sharakhov IV. Cytogenetic analysis of Anopheles ovengensis revealed high structural divergence of chromosomes in the Anopheles nili group. INFECTION GENETICS AND EVOLUTION 2013; 16:341-8. [PMID: 23523820 DOI: 10.1016/j.meegid.2013.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/25/2013] [Accepted: 03/05/2013] [Indexed: 01/15/2023]
Abstract
Cytogenetic analysis is an informative classical approach to understanding the relationships among members in a group of closely related species of mosquitoes. Anopheles ovengensis is a recently discovered species of the Anopheles nili group and is one of the important malaria vectors in the African equatorial forest. This study characterized polytene chromosomes of An. ovengensis and compared them with polytene chromosomes of An. nili. Using fluorescent in situ hybridization and chromosome banding pattern comparison we have established correspondence between chromosomal arms of An. ovengensis and An. nili. Analysis of chromosome morphology in the two species revealed a limited similarity in the banding patterns. The most extensive reorganization occurs in pericentromeric and intercalary heterochromatin. Chromosomes of An. ovengensis are joined together by a diffuse chromocenter and they have two large regions of intercalary heterochromatin in arms 2L and 3R. In contrast, the chromocenter and intercalary heterochromatin are not seen in An. nili chromosomes. Comparative analysis of the arm association suggests the occurrence of a whole-arm translocation between the two members of the group. The observed, substantial reorganizations of chromosome structure implies either a rapid rate of chromosome evolution in the An. nili group, or that the two species belong to different taxonomic groups within subgenus Cellia.
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Ndo C, Simard F, Kengne P, Awono-Ambene P, Morlais I, Sharakhov I, Fontenille D, Antonio-Nkondjio C. Cryptic genetic diversity within the Anopheles nili group of malaria vectors in the equatorial forest area of Cameroon (Central Africa). PLoS One 2013; 8:e58862. [PMID: 23516565 PMCID: PMC3597579 DOI: 10.1371/journal.pone.0058862] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/07/2013] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The Anopheles nili group of mosquitoes includes important vectors of human malaria in equatorial forest and humid savannah regions of sub-Saharan Africa. However, it remains largely understudied, and data on its populations' bionomics and genetic structure are crucially lacking. Here, we used a combination of nuclear (i.e. microsatellite and ribosomal DNA) and mitochondrial DNA markers to explore and compare the level of genetic polymorphism and divergence among populations and species of the group in the savannah and forested areas of Cameroon, Central Africa. PRINCIPAL FINDINGS All the markers provided support for the current classification within the An. nili group. However, they revealed high genetic heterogeneity within An. nili s.s. in deep equatorial forest environment. Nuclear markers showed the species to be composed of five highly divergent genetic lineages that differed by 1.8 to 12.9% of their Internal Transcribed Spacer 2 (ITS2) sequences, implying approximate divergence time of 0.82 to 5.86 million years. However, mitochondrial data only detected three major subdivisions, suggesting different evolutionary histories of the markers. CONCLUSIONS/SIGNIFICANCE This study enlightened additional cryptic genetic diversity within An. nili s.s. in the deep equatorial forest environment of South Cameroon, reflecting a complex demographic history for this major vector of malaria in this environment. These preliminary results should be complemented by further studies which will shed light on the distribution, epidemiological importance and evolutionary history of this species group in the African rainforest, providing opportunities for in-depth comparative studies of local adaptation and speciation in major African malaria vectors.
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Affiliation(s)
- Cyrille Ndo
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale, Yaoundé, Cameroon.
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Kamali M, Xia A, Tu Z, Sharakhov IV. A new chromosomal phylogeny supports the repeated origin of vectorial capacity in malaria mosquitoes of the Anopheles gambiae complex. PLoS Pathog 2012; 8:e1002960. [PMID: 23055932 PMCID: PMC3464210 DOI: 10.1371/journal.ppat.1002960] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/27/2012] [Indexed: 11/28/2022] Open
Abstract
Understanding phylogenetic relationships within species complexes of disease vectors is crucial for identifying genomic changes associated with the evolution of epidemiologically important traits. However, the high degree of genetic similarity among sibling species confounds the ability to determine phylogenetic relationships using molecular markers. The goal of this study was to infer the ancestral–descendant relationships among malaria vectors and nonvectors of the Anopheles gambiae species complex by analyzing breakpoints of fixed chromosomal inversions in ingroup and several outgroup species. We identified genes at breakpoints of fixed overlapping chromosomal inversions 2Ro and 2Rp of An. merus using fluorescence in situ hybridization, a whole-genome mate-paired sequencing, and clone sequencing. We also mapped breakpoints of a chromosomal inversion 2La (common to An. merus, An. gambiae, and An. arabiensis) in outgroup species using a bioinformatics approach. We demonstrated that the “standard” 2R+p arrangement and “inverted” 2Ro and 2La arrangements are present in outgroup species Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The data indicate that the ancestral species of the An. gambiae complex had the 2Ro, 2R+p, and 2La chromosomal arrangements. The “inverted” 2Ro arrangement uniquely characterizes a malaria vector An. merus as the basal species in the complex. The rooted chromosomal phylogeny implies that An. merus acquired the 2Rp inversion and that its sister species An. gambiae acquired the 2R+o inversion from the ancestral species. The karyotype of nonvectors An. quadriannulatus A and B was derived from the karyotype of the major malaria vector An. gambiae. We conclude that the ability to effectively transmit human malaria had originated repeatedly in the complex. Our findings also suggest that saltwater tolerance originated first in An. merus and then independently in An. melas. The new chromosomal phylogeny will facilitate identifying the association of evolutionary genomic changes with epidemiologically important phenotypes. Malaria causes more than one million deaths every year, mostly among children in Sub-Saharan Africa. Anopheles mosquitoes are exclusive vectors of human malaria. Many malaria vectors belong to species complexes, and members within these complexes can vary significantly in their ecological adaptations and ability to transmit the parasite. To better understand evolution of epidemiologically important traits, we studied relationships among nonvector and vector species of the African Anopheles gambiae complex. We analyzed gene orders at genomic regions where evolutionary breaks of chromosomal inversions occurred in members of the complex and compared them with gene orders in species outside the complex. This approach allowed us to identify ancient and recent gene orders for three chromosomal inversions. Surprisingly, the more ancestral chromosomal arrangements were found in mosquito species that are vectors of human malaria, while the more derived arrangements were found in both nonvectors and vectors. Our finding strongly suggests that the increased ability to transmit human malaria originated repeatedly during the recent evolution of these African mosquitoes. This knowledge can be used to identify specific genetic changes associated with the human blood choice and ecological adaptations.
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Affiliation(s)
- Maryam Kamali
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Ai Xia
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Zhijian Tu
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Igor V. Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- * E-mail:
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Improving the population genetics toolbox for the study of the African malaria vector Anopheles nili: microsatellite mapping to chromosomes. Parasit Vectors 2011; 4:202. [PMID: 22011455 PMCID: PMC3222614 DOI: 10.1186/1756-3305-4-202] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 10/19/2011] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Anopheles nili is a major vector of malaria in the humid savannas and forested areas of sub-Saharan Africa. Understanding the population genetic structure and evolutionary dynamics of this species is important for the development of an adequate and targeted malaria control strategy in Africa. Chromosomal inversions and microsatellite markers are commonly used for studying the population structure of malaria mosquitoes. Physical mapping of these markers onto the chromosomes further improves the toolbox, and allows inference on the demographic and evolutionary history of the target species. RESULTS Availability of polytene chromosomes allowed us to develop a map of microsatellite markers and to study polymorphism of chromosomal inversions. Nine microsatellite markers were mapped to unique locations on all five chromosomal arms of An. nili using fluorescent in situ hybridization (FISH). Probes were obtained from 300-483 bp-long inserts of plasmid clones and from 506-559 bp-long fragments amplified with primers designed using the An. nili genome assembly generated on an Illumina platform. Two additional loci were assigned to specific chromosome arms of An. nili based on in silico sequence similarity and chromosome synteny with Anopheles gambiae. Three microsatellites were mapped inside or in the vicinity of the polymorphic chromosomal inversions 2Rb and 2Rc. A statistically significant departure from Hardy-Weinberg equilibrium, due to a deficit in heterozygotes at the 2Rb inversion, and highly significant linkage disequilibrium between the two inversions, were detected in natural An. nili populations collected from Burkina Faso. CONCLUSIONS Our study demonstrated that next-generation sequencing can be used to improve FISH for microsatellite mapping in species with no reference genome sequence. Physical mapping of microsatellite markers in An. nili showed that their cytological locations spanned the entire five-arm complement, allowing genome-wide inferences. The knowledge about polymorphic inversions and chromosomal locations of microsatellite markers has been useful for explaining differences in genetic variability across loci and significant differentiation observed among natural populations of An. nili.
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Kamali M, Sharakhova MV, Baricheva E, Karagodin D, Tu Z, Sharakhov IV. An integrated chromosome map of microsatellite markers and inversion breakpoints for an Asian malaria mosquito, Anopheles stephensi. ACTA ACUST UNITED AC 2011; 102:719-26. [PMID: 21810771 DOI: 10.1093/jhered/esr072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Anopheles stephensi is one of the major vectors of malaria in the Middle East and Indo-Pakistan subcontinent. Understanding the population genetic structure of malaria mosquitoes is important for developing adequate and successful vector control strategies. Commonly used markers for inferring anopheline taxonomic and population status include microsatellites and chromosomal inversions. Knowledge about chromosomal locations of microsatellite markers with respect to polymorphic inversions could be useful for better understanding a genetic structure of natural populations. However, fragments with microsatellites used in population genetic studies are usually too short for successful labeling and hybridization with chromosomes. We designed new primers for amplification of microsatellite loci identified in the A. stephensi genome sequenced with next-generation technologies. Twelve microsatellites were mapped to polytene chromosomes from ovarian nurse cells of A. stephensi using fluorescent in situ hybridization. All microsatellites hybridized to unique locations on autosomes, and 7 of them localized to the largest arm 2R. Ten microsatellites were mapped inside the previously described polymorphic chromosomal inversions, including 4 loci located inside the widespread inversion 2Rb. We analyzed microsatellite-based population genetic data available for A. stephensi in light of our mapping results. This study demonstrates that the chromosomal position of microsatellites may affect estimates of population genetic parameters and highlights the importance of developing physical maps for nonmodel organisms.
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Affiliation(s)
- Maryam Kamali
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
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