1
|
Gstöttenmayer F, Moyaba P, Rodriguez M, Mulandane FC, Mucache HN, Neves L, De Beer C, Ravel S, De Meeûs T, Mach RL, Vreysen MJB, Abd-Alla AM. Development and characterization of microsatellite markers for the tsetse species Glossina brevipalpis and preliminary population genetics analyses. Parasite 2023; 30:34. [PMID: 37712836 PMCID: PMC10503490 DOI: 10.1051/parasite/2023038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/23/2023] [Indexed: 09/16/2023] Open
Abstract
Tsetse flies, the vectors of African trypanosomes are of key medical and economic importance and one of the constraints for the development of Africa. Tsetse fly control is one of the most effective and sustainable strategies used for controlling the disease. Knowledge about population structure and level of gene flow between neighbouring populations of the target vector is of high importance to develop appropriate strategies for implementing effective management programmes. Microsatellites are commonly used to identify population structure and assess dispersal of the target populations and have been developed for several tsetse species but were lacking for Glossina brevipalpis. In this study, we screened the genome of G. brevipalpis to search for suitable microsatellite markers and nine were found to be efficient enough to distinguish between different tsetse populations. The availability of these novel microsatellite loci will help to better understand the population biology of G. brevipalpis and to assess the level of gene flow between different populations. Such information will help with the development of appropriate strategies to implement the sterile insect technique (SIT) in the framework of an area-wide integrated pest management (AW-IPM) approach to manage tsetse populations and ultimately address the trypanosomoses problem in these targeted areas.
Collapse
Affiliation(s)
- Fabian Gstöttenmayer
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna International Centre P.O. Box 100 1400 Vienna Austria
| | - Percy Moyaba
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna International Centre P.O. Box 100 1400 Vienna Austria
- Epidemiology, Parasites and Vectors, Agricultural Research Council-Onderstepoort Veterinary Research 100 Soutpan Road Private Bag X05 Onderstepoort 0110 South Africa
| | - Montse Rodriguez
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna International Centre P.O. Box 100 1400 Vienna Austria
| | - Fernando C. Mulandane
- University Eduardo Mondlane, Centro de Biotecnologia Av. de Moçambique Km 1.5 Maputo Mozambique
| | - Hermógenes N. Mucache
- University Eduardo Mondlane, Centro de Biotecnologia Av. de Moçambique Km 1.5 Maputo Mozambique
| | - Luis Neves
- University Eduardo Mondlane, Centro de Biotecnologia Av. de Moçambique Km 1.5 Maputo Mozambique
- University of Pretoria, Department of Veterinary Tropical Diseases Private Bag X04 Onderstepoort 0110 South Africa
| | - Chantel De Beer
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna International Centre P.O. Box 100 1400 Vienna Austria
| | - Sophie Ravel
- University of Montpellier, Cirad, IRD, Intertryp Campus International de Baillarguet 34398 Montpellier Cedex 5 France
| | - Thierry De Meeûs
- University of Montpellier, Cirad, IRD, Intertryp Campus International de Baillarguet 34398 Montpellier Cedex 5 France
| | - Robert L. Mach
- Institute of Chemical, Environmental, and Bioscience Engineering, Vienna University of Technology Gumpendorfer Straße 1a 1060 Vienna Austria
| | - Marc J. B. Vreysen
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna International Centre P.O. Box 100 1400 Vienna Austria
| | - Adly M.M. Abd-Alla
- Insect Pest Control Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Vienna International Centre P.O. Box 100 1400 Vienna Austria
| |
Collapse
|
2
|
Mayoke A, Ouma JO, Mireji PO, Omondi SF, Muya SM, Itoua A, Okoth SO, Bateta R. Population Structure and Migration Patterns of the Tsetse Fly Glossina fuscipes in Congo-Brazzaville. Am J Trop Med Hyg 2020; 104:917-927. [PMID: 33372648 PMCID: PMC7941806 DOI: 10.4269/ajtmh.20-0774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/17/2020] [Indexed: 11/07/2022] Open
Abstract
Tsetse flies of the palpalis group, particularly Glossina fuscipes, are the main vectors of human African trypanosomiasis or sleeping sickness in Congo-Brazzaville. They transmit the deadly human parasite, Trypanosoma brucei gambiense and other trypanosomes that cause animal trypanosomiasis. Knowledge on diversity, population structure, population size, and gene flow is a prerequisite for designing effective tsetse control strategies. There is limited published information on these parameters including migration patterns of G. fuscipes in Congo-Brazzaville. We genotyped 288 samples of G. fuscipes from Bomassa (BMSA), Bouemba (BEMB), and Talangai (TLG) locations at 10 microsatellite loci and determined levels of genetic diversity, differentiation, structuring, and gene flow among populations. We observed high genetic diversity in all three localities. Mean expected heterozygosity was 0.77 ± 0.04, and mean allelic richness was 11.2 ± 1.35. Deficiency of heterozygosity was observed in all populations with positive and significant F IS values (0.077-0.149). Structure analysis revealed three clusters with genetic admixtures, evidence of closely related but potentially different taxa within G. fuscipes. Genetic differentiation indices were low but significant (F ST = 0.049, P < 0.05), indicating ongoing gene flow countered with a stronger force of drift. We recorded significant migration from all the three populations, suggesting exchange of genetic information between and among locations. Ne estimates revealed high and infinite population sizes in BEMB and TLG. These critical factors should be considered when planning area-wide tsetse control interventions in the country to prevent resurgence of tsetse from relict populations and/or reinvasion of cleared habitats.
Collapse
Affiliation(s)
- Abraham Mayoke
- Department of Molecular Biology and Biotechnology, Pan African University Institute for Basic Sciences, Technology and Innovation, Nairobi, Kenya
- Kenya Forestry Research Institute, Nairobi, Kenya
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- Marien Ngouabi University, Brazzaville, Congo
| | - Johnson O. Ouma
- African Technical Research Centre, Vector Health International, Arusha, Tanzania
| | - Paul O. Mireji
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | | | - Shadrack M. Muya
- School of Biological Sciences, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Andre Itoua
- Laboratoire de Parasitologie, Centre de Recherche Veterinaire et Zootechniques, Brazzaville, Congo
| | - Sylvance O. Okoth
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Rosemary Bateta
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| |
Collapse
|
3
|
Ravel S, Séré M, Manangwa O, Kagbadouno M, Mahamat MH, Shereni W, Okeyo WA, Argiles-Herrero R, De Meeûs T. Developing and quality testing of microsatellite loci for four species of Glossina. INFECTION GENETICS AND EVOLUTION 2020; 85:104515. [PMID: 32861909 DOI: 10.1016/j.meegid.2020.104515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 07/29/2020] [Accepted: 08/24/2020] [Indexed: 11/15/2022]
Abstract
Microsatellite loci still represent valuable resources for the study of the population biology of non-model organisms. Discovering or adapting new suitable microsatellite markers in species of interest still represents a useful task, especially so for non-model organisms as tsetse flies (genus Glossina), which remain a serious threat to the health of humans and animals in sub-Saharan Africa. In this paper, we present the development of new microsatellite loci for four species of Glossina: two from the Morsitans group, G. morsitans morsitans (Gmm) from Zimbabwe, G. pallidipes (Gpalli) from Tanzania; and the other two from the Palpalis group, G. fuscipes fuscipes (Gff) from Chad, and G. palpalis gambiensis (Gpg) from Guinea. We found frequent short allele dominance and null alleles. Stuttering could also be found and amended when possible. Cryptic species seemed to occur frequently in all taxa but Gff. This explains why it may be difficult finding ecumenical primers, which thus need adaptation according to each taxonomic and geographic context. Amplification problems occurred more often in published old markers, and Gmm and Gpg were the most affected (stronger heterozygote deficits). Trinucleotide markers displayed selection signature in some instances (Gmm). Combining old and new loci, for Gmm, eight loci can be safely used (with correction for null alleles); and five seem particularly promising; for Gpalli, only five to three loci worked well, depending on the clade, which means that the use of loci from other species (four morsitans loci seemed to work well), or other new primers will need to be used; for Gff, 14 loci behaved well, but with null alleles, seven of which worked very well; and for G. palpalis sl, only four loci, needing null allele and stuttering corrections seem to work well, and other loci from the literature are thus needed, including X-linked markers, five of which seem to work rather well (in females only), but new markers will probably be needed. Finally, the high proportion of X-linked markers (around 30%) was explained by the non-Y DNA quantity and chromosome structure of tsetse flies studied so far.
Collapse
Affiliation(s)
- Sophie Ravel
- Intertryp, IRD, Cirad, Univ Montpellier, Montpellier, France
| | - Modou Séré
- University of Dédougou, Dédougou B.P. 176, Burkina Faso
| | - Oliver Manangwa
- Vector and Vector Borne Disease Research Institute, P.O.Box 1026, Tanga, Tanzania
| | - Moise Kagbadouno
- Programme National de Lutte contre la THA (PNLTHA), Conakry, Guinea
| | | | - William Shereni
- Ministry of Lands, Agriculture, Water and Rural Resettlement, Harare, Zimbabwe
| | | | - Rafael Argiles-Herrero
- Insect Pest Control Sub-Programme, Joint Food and Agriculture Organization of the United Nations/International Atomic Energy Agency Programme of Nuclear Techniques in Food and Agriculture, Vienna A-1400, Austria
| | | |
Collapse
|
4
|
Saarman NP, Opiro R, Hyseni C, Echodu R, Opiyo EA, Dion K, Johnson T, Aksoy S, Caccone A. The population genomics of multiple tsetse fly (Glossina fuscipes fuscipes) admixture zones in Uganda. Mol Ecol 2019; 28:66-85. [PMID: 30471158 DOI: 10.1111/mec.14957] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 10/26/2018] [Accepted: 11/05/2018] [Indexed: 11/28/2022]
Abstract
Understanding the mechanisms that enforce, maintain or reverse the process of speciation is an important challenge in evolutionary biology. This study investigates the patterns of divergence and discusses the processes that form and maintain divergent lineages of the tsetse fly Glossina fuscipes fuscipes in Uganda. We sampled 251 flies from 18 sites spanning known genetic lineages and the four admixture zones between them. We apply population genomics, hybrid zone and approximate Bayesian computation to the analysis of three types of genetic markers: 55,267 double-digest restriction site-associated DNA (ddRAD) SNPs to assess genome-wide admixture, 16 microsatellites to provide continuity with published data and accurate biogeographic modelling, and a 491-bp fragment of mitochondrial cytochrome oxidase I and II to infer maternal inheritance patterns. Admixture zones correspond with regions impacted by the reorganization of Uganda's river networks that occurred during the formation of the West African Rift system over the last several hundred thousand years. Because tsetse fly population distributions are defined by rivers, admixture zones likely represent both old and new regions of secondary contact. Our results indicate that older hybrid zones contain mostly parental types, while younger zones contain variable hybrid types resulting from multiple generations of interbreeding. These findings suggest that reproductive barriers are nearly complete in the older admixture zones, while nearly absent in the younger admixture zones. Findings are consistent with predictions of hybrid zone theory: Populations in zones of secondary contact transition rapidly from early to late stages of speciation or collapse all together.
Collapse
Affiliation(s)
- Norah P Saarman
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut
| | - Robert Opiro
- Department of Biology, Faculty of Science, Gulu University, Uganda
| | - Chaz Hyseni
- Department of Biology, University of Mississippi, Oxford, Mississippi
| | - Richard Echodu
- Department of Biology, Faculty of Science, Gulu University, Uganda
| | | | - Kirstin Dion
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut
| | - Thomas Johnson
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut
| | - Serap Aksoy
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut
| |
Collapse
|
5
|
Augustinos AA, Meki IK, Demirbas-Uzel G, Ouédraogo GMS, Saridaki A, Tsiamis G, Parker AG, Abd-Alla AMM, Bourtzis K. Nuclear and Wolbachia-based multimarker approach for the rapid and accurate identification of tsetse species. BMC Microbiol 2018; 18:147. [PMID: 30470190 PMCID: PMC6251096 DOI: 10.1186/s12866-018-1295-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Tsetse flies (Diptera: Glossinidae) are solely responsible for the transmission of African trypanosomes, causative agents of sleeping sickness in humans and nagana in livestock. Due to the lack of efficient vaccines and the emergence of drug resistance, vector control approaches such as the sterile insect technique (SIT), remain the most effective way to control disease. SIT is a species-specific approach and therefore requires accurate identification of natural pest populations at the species level. However, the presence of morphologically similar species (species complexes and sub-species) in tsetse flies challenges the successful implementation of SIT-based population control. Results In this study, we evaluate different molecular tools that can be applied for the delimitation of different Glossina species using tsetse samples derived from laboratory colonies, natural populations and museum specimens. The use of mitochondrial markers, nuclear markers (including internal transcribed spacer 1 (ITS1) and different microsatellites), and bacterial symbiotic markers (Wolbachia infection status) in combination with relatively inexpensive techniques such as PCR, agarose gel electrophoresis, and to some extent sequencing provided a rapid, cost effective, and accurate identification of several tsetse species. Conclusions The effectiveness of SIT benefits from the fine resolution of species limits in nature. The present study supports the quick identification of large samples using simple and cost effective universalized protocols, which can be easily applied by countries/laboratories with limited resources and expertise. Electronic supplementary material The online version of this article (10.1186/s12866-018-1295-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Antonios A Augustinos
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria
| | - Irene K Meki
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria
| | - Guler Demirbas-Uzel
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria
| | - Gisele M S Ouédraogo
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria.,Ecole National de l'Elevage et de la Santé Animale, 03 BP 7026, Ouagadougou 03, Burkina Faso
| | - Aggeliki Saridaki
- Department of Environmental and Natural Resources Management, University of Patras, Agrinio, Greece
| | - George Tsiamis
- Department of Environmental and Natural Resources Management, University of Patras, Agrinio, Greece
| | - Andrew G Parker
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria
| | - Adly M M Abd-Alla
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna International Centre, P.O. Box 100, 1400, Vienna, Austria.
| |
Collapse
|
6
|
Dyer NA, Ravel S, Choi KS, Darby AC, Causse S, Kapitano B, Hall MJR, Steen K, Lutumba P, Madinga J, Torr SJ, Okedi LM, Lehane MJ, Donnelly MJ. Cryptic diversity within the major trypanosomiasis vector Glossina fuscipes revealed by molecular markers. PLoS Negl Trop Dis 2011; 5:e1266. [PMID: 21858237 PMCID: PMC3153427 DOI: 10.1371/journal.pntd.0001266] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 06/21/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The tsetse fly Glossina fuscipes s.l. is responsible for the transmission of approximately 90% of cases of human African trypanosomiasis (HAT) or sleeping sickness. Three G. fuscipes subspecies have been described, primarily based upon subtle differences in the morphology of their genitalia. Here we describe a study conducted across the range of this important vector to determine whether molecular evidence generated from nuclear DNA (microsatellites and gene sequence information), mitochondrial DNA and symbiont DNA support the existence of these taxa as discrete taxonomic units. PRINCIPAL FINDINGS The nuclear ribosomal Internal transcribed spacer 1 (ITS1) provided support for the three subspecies. However nuclear and mitochondrial sequence data did not support the monophyly of the morphological subspecies G. f. fuscipes or G. f. quanzensis. Instead, the most strongly supported monophyletic group was comprised of flies sampled from Ethiopia. Maternally inherited loci (mtDNA and symbiont) also suggested monophyly of a group from Lake Victoria basin and Tanzania, but this group was not supported by nuclear loci, suggesting different histories of these markers. Microsatellite data confirmed strong structuring across the range of G. fuscipes s.l., and was useful for deriving the interrelationship of closely related populations. CONCLUSION/SIGNIFICANCE We propose that the morphological classification alone is not used to classify populations of G. fuscipes for control purposes. The Ethiopian population, which is scheduled to be the target of a sterile insect release (SIT) programme, was notably discrete. From a programmatic perspective this may be both positive, given that it may reflect limited migration into the area or negative if the high levels of differentiation are also reflected in reproductive isolation between this population and the flies to be used in the release programme.
Collapse
Affiliation(s)
- Naomi A. Dyer
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Sophie Ravel
- Institut de Recherche pour le Développement (IRD), UMR 177 IRD-CIRAD, LRCT Campus International de Baillarguet, Montpellier, France
| | - Kwang-Shik Choi
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Alistair C. Darby
- School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Sandrine Causse
- Institut de Recherche pour le Développement (IRD), UMR 177 IRD-CIRAD, LRCT Campus International de Baillarguet, Montpellier, France
| | - Berisha Kapitano
- Southern Rift Valley of Ethiopia Tsetse Eradication Project, Hawassa, Ethiopia
| | | | - Keith Steen
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Pascal Lutumba
- Department of Tropical Medicine, School of Medicine, Kinshasa University, Kinshasa, Democratic Republic of Congo
| | - Joules Madinga
- Department of Tropical Medicine, School of Medicine, Kinshasa University, Kinshasa, Democratic Republic of Congo
| | - Steve J. Torr
- Agriculture, Health and Environment Group, National Resources Institute, University of Greenwich, Chatham Maritime, United Kingdom
| | - Loyce M. Okedi
- National Livestock Resources Research Institute, Tororo, Uganda
| | - Michael J. Lehane
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Martin J. Donnelly
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Microbiology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
| |
Collapse
|
7
|
Bonomi A, Bassetti F, Gabrieli P, Beadell J, Falchetto M, Scolari F, Gomulski LM, Regazzini E, Ouma JO, Caccone A, Okedi LM, Attardo GM, Guglielmino CR, Aksoy S, Malacrida AR. Polyandry is a common event in wild populations of the Tsetse fly Glossina fuscipes fuscipes and may impact population reduction measures. PLoS Negl Trop Dis 2011; 5:e1190. [PMID: 21666797 PMCID: PMC3110164 DOI: 10.1371/journal.pntd.0001190] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 04/20/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Glossina fuscipes fuscipes is the main vector of human and animal trypanosomiasis in Africa, particularly in Uganda. Attempts to control/eradicate this species using biological methods require knowledge of its reproductive biology. An important aspect is the number of times a female mates in the wild as this influences the effective population size and may constitute a critical factor in determining the success of control methods. To date, polyandry in G.f. fuscipes has not been investigated in the laboratory or in the wild. Interest in assessing the presence of remating in Ugandan populations is driven by the fact that eradication of this species is at the planning stage in this country. METHODOLOGY/PRINCIPAL FINDINGS Two well established populations, Kabukanga in the West and Buvuma Island in Lake Victoria, were sampled to assess the presence and frequency of female remating. Six informative microsatellite loci were used to estimate the number of matings per female by genotyping sperm preserved in the female spermathecae. The direct count of the minimum number of males that transferred sperm to the spermathecae was compared to Maximum Likelihood and Bayesian probability estimates. The three estimates provided evidence that remating is common in the populations but the frequency is substantially different: 57% in Kabukanga and 33% in Buvuma. CONCLUSIONS/SIGNIFICANCE The presence of remating, with females maintaining sperm from different mates, may constitute a critical factor in cases of re-infestation of cleared areas and/or of residual populations. Remating may enhance the reproductive potential of re-invading propagules in terms of their effective population size. We suggest that population age structure may influence remating frequency. Considering the seasonal demographic changes that this fly undergoes during the dry and wet seasons, control programmes based on SIT should release large numbers of sterile males, even in residual surviving target populations, in the dry season.
Collapse
Affiliation(s)
- Angelica Bonomi
- Department of Animal Biology, University of Pavia, Pavia, Italy
| | | | - Paolo Gabrieli
- Department of Animal Biology, University of Pavia, Pavia, Italy
| | - Jon Beadell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America
| | - Marco Falchetto
- Department of Animal Biology, University of Pavia, Pavia, Italy
| | | | | | | | - Johnson O. Ouma
- Trypanosomiasis Research Centre, Kenya Agricultural Research Institute, Kikuyu, Kenya
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America
| | - Loyce M. Okedi
- National Livestock Resources Research Institute, Tororo, Uganda
| | - Geoffrey M. Attardo
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
| | | | - Serap Aksoy
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Anna R. Malacrida
- Department of Animal Biology, University of Pavia, Pavia, Italy
- * E-mail:
| |
Collapse
|
8
|
Beadell JS, Hyseni C, Abila PP, Azabo R, Enyaru JCK, Ouma JO, Mohammed YO, Okedi LM, Aksoy S, Caccone A. Phylogeography and population structure of Glossina fuscipes fuscipes in Uganda: implications for control of tsetse. PLoS Negl Trop Dis 2010; 4:e636. [PMID: 20300518 PMCID: PMC2838784 DOI: 10.1371/journal.pntd.0000636] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 01/29/2010] [Indexed: 11/18/2022] Open
Abstract
Background Glossina fuscipes fuscipes, a riverine species of tsetse, is the main vector of both human and animal trypanosomiasis in Uganda. Successful implementation of vector control will require establishing an appropriate geographical scale for these activities. Population genetics can help to resolve this issue by characterizing the extent of linkage among apparently isolated groups of tsetse. Methodology/Principal Findings We conducted genetic analyses on mitochondrial and microsatellite data accumulated from approximately 1000 individual tsetse captured in Uganda and neighboring regions of Kenya and Sudan. Phylogeographic analyses suggested that the largest scale genetic structure in G. f. fuscipes arose from an historical event that divided two divergent mitochondrial lineages. These lineages are currently partitioned to northern and southern Uganda and co-occur only in a narrow zone of contact extending across central Uganda. Bayesian assignment tests, which provided evidence for admixture between northern and southern flies at the zone of contact and evidence for northerly gene flow across the zone of contact, indicated that this structure may be impermanent. On the other hand, microsatellite structure within the southern lineage indicated that gene flow is currently limited between populations in western and southeastern Uganda. Within regions, the average FST between populations separated by less than 100 km was less than ∼0.1. Significant tests of isolation by distance suggested that gene flow is ongoing between neighboring populations and that island populations are not uniformly more isolated than mainland populations. Conclusions/Significance Despite the presence of population structure arising from historical colonization events, our results have revealed strong signals of current gene flow within regions that should be accounted for when planning tsetse control in Uganda. Populations in southeastern Uganda appeared to receive little gene flow from populations in western or northern Uganda, supporting the feasibility of area wide control in the Lake Victoria region by the Pan African Tsetse and Trypanosomiasis Eradication Campaign. Glossina fuscipes fuscipes is the most common species of tsetse in Uganda, where it transmits human sleeping sickness and nagana, a related disease of cattle. A consortium of African countries dedicated to controlling these diseases is poised to begin area wide control of tsetse, but a critical question remains: What is the most appropriate geographical scale for these activities? To address this question, we used population genetics to determine the extent of linkage between populations of tsetse confined to discrete patches of riverine habitat. Our results suggest that Uganda was colonized by two distinct lineages of G. f. fuscipes, which now co-occur only in a narrow band across central Uganda. Evidence for interbreeding at the zone of contact and movement of genes from the south to the north suggest that this historical genetic structure may dissolve in the future. At smaller scales, we have demonstrated that exchange of genes among neighboring populations via dispersal is at equilibrium with the differentiating force of genetic drift. Our results highlight the need for investment in vector control programs that account for the linkage observed among tsetse populations. Given its genetic isolation and its location at the far edge of G. fuscipes' range, the Lake Victoria region appears to be an appropriate target for area wide control.
Collapse
Affiliation(s)
- Jon S. Beadell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
| | - Chaz Hyseni
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America
| | | | - Rogers Azabo
- National Livestock Resources Research Institute, Tororo, Uganda
| | - John C. K. Enyaru
- Department of Biochemistry, Faculty of Science, Makerere University, Kampala, Uganda
| | - Johnson O. Ouma
- Trypanosomiasis Research Centre, Kenya Agricultural Research Institute, Kikuyu, Kenya
| | - Yassir O. Mohammed
- Central Veterinary Research Laboratories, Animal Resources Research Corporation, Khartoum, Sudan
| | - Loyce M. Okedi
- National Livestock Resources Research Institute, Tororo, Uganda
| | - Serap Aksoy
- Department of Epidemiology and Public Health, Yale University, New Haven, Connecticut, United States of America
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America
| |
Collapse
|