Guiyun YanProfessor Joint appointment, Ecology & Evolutionary Biology |
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Research Interests |
Population ecology and genetics of host-parasite interactions, malaria epidemiology | |
| Appointments |
Dr. Yan's lab members: Dr. Laith Yakob, Postdoc fellow Dr. Meihui Wang, Postdoc fellow Dr. Mariangela Bonizzoni, Postdoc fellow Dr. Anne Vardo-Zalik, Postdoc fellow Dr. Daibin Zhong, Assistant Scientist Dr. Guofa Zhou, Associate Scientist Thomas Gilbreath, Ph.D. Student Sarah Daguplo, Lab manager |
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Research Abstract |
Ecology of African Highland Malaria Malaria is a major public health problem in sub-Saharan Africa. The East African highlands (1,500m above sea level) were either free of malaria or had very low incidences; however, since late 1980s malaria epidemics have frequently occurred in some highland areas. We examine the mechanisms leading to the resurgence of malaria in African high-elevation areas, including climate, land use, topography and antimalarial drug resistance in the Plasmodium parasites. We found that deforestation and swamp reclamation affect microclimatic and nutritional conditions of larval habitats, increase the survivorship of malaria vectors at larval and adult stages, shorten the development time of malaria parasites, and significantly increase mosquito vectorial capacity. We are developing models to predict the spread of malaria infections in an epidemic, and evaluating new malaria vector control methods for epidemic prevention. Population Biology of African Malaria Vectors We are interested in 1) larval population regulation of Anopheles gambiae and An. funestus mosquito, and 2) dry-season survival strategy of mosquito populations. Previously, we have determined green algae are important food source for anopheline larvae. We are currently determining the species composition of green algae in larval habitats and identifying the gut contents of mosquito larvae using bar-coding technique. Using bioassays we determine the nutritional values of algae to mosquito larvae and adults. We are also interested in the potential tradeoffs between larval nutritional status and adult survivorship, blood feeding and vectorial capacity. We are examining physiology, ecology and genetics of desiccation resistance, and age-grading molecular marker development for An. gambiae. Evolutionary Genetics of Host Resistance to Parasitism Many parasites, including some protozoans, nematodes, trematodes, cestodes and all acanthocephalans, require intermediate hosts to complete their life cycles, but there is virtually no knowledge on the evolution of life history of this type parasites. We use the rat tapeworm parasite (Hymenolepis diminuta) and its intermediate host, the red flour beetle (Tribolium castaneum) as a model system to test the hypothesis that the evolution of resistance is constrained by fitness costs associated with resistance. Using QTL mapping techniques, we have localized the QTLs that influencing both beetle resistance to infection and beetle fitness. We are currently conducting high-resolution mapping and identifying resistance candidate genes. We plan to use parental RNAi method to determine whether knockdown of resistance gene expression has effects on beetle’s fitness and beetle’s resistance to tapeworm infection. |
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| Publications |
Zhou G., N. Minakawa, A. K. Githeko and G. Yan. 2004. Association between climate variability and malaria epidemics in the east African highlands. PNAS USA 101: 2375-2380. Sharakhov IV, Braginets O., Grushko O., Cohuet A., Guelbeogo W. M., Bocollini D., Weill M., Sagnon N’F., Fontenille D., Yan G., Besansky N. J. 2004. A microsatellite physical map of the African human malaria vector Anopheles funestus. J. Heredity 95: 29-34. Gouagna L.C., Ferguson H.M., Okech B.A., Killeen G.F., Kabiru, E.W., Beier J.C., Githure J.I. and G. Yan. 2004. Plasmodium falciparum malaria disease manifestations in humans and transmission to Anopheles gambiae: a field study in Western Kenya. Parasitology 128: 235-243. Minakawa N., S. Munga, F. Atieli, E. Mushinzimana, G. Zhou, A. Githeko, and G. Yan. 2005. Spatial distribution of anopheline larval habitats in western Kenyan highlands: effects of land cover types and topography. Am. J. Trop. Med. Hyg.73: 157–165. Munyekenye G.O., A. K. Githeko, G. Zhou, E. Mushinzimana, N. Minakawa, and G. Yan. 2005. Spatial analysis of Plasmodium infections in western Kenya highlands. Emerging Infectious Diseases 10: 1571- 1577. Zhong D., A. Pai and G. Yan. 2005. Costly resistance to parasitism: evidence from simultaneous quantitative trait loci mapping for resistance and fitness. Genetics 169:2127-2135. Afrane Y. A., G. Zhou, B. W. Lawson, A. K. Githeko, and G. Yan. 2006. Effects of microclimatic changes due to deforestation on the survivorship and reproductive fitness of Anopheles gambiae in western Kenya highlands. Am. J. Trop. Med. Hyg.74: 772 – 778. Menge, D. M., D. Zhong, T. Guda, L. Gouagna, J. Githure, J. C. Beier, and G. Yan. 2006. Quantitative trait loci controlling refractoriness to Plasmodium falciparum in natural Anopheles gambiae mosquitoes from a malaria endemic region in western Kenya. Genetics 173: 235-241. Munga S., N. Minakawa, G. Zhou, E. Mushinzimana, O. J. Barrack, A. K. Githeko, and G. Yan. 2006. Association between landcover and production of malaria vectors in the western Kenyan highland. Am. J. Trop. Med. Hyg.74: 69–75. Mushinzimana E., S. Munga, N. Minakawa, L. Li, C. Feng, L. Bian, U. Kitron, C. Schmidt, L. Beck, G. Zhou, A. K. Githeko, and G. Yan. 2006. Comparison of three remote sensors for identification of anopheline mosquito larval habitats in western Kenya highlands. Malaria Journal 5: 13. Yang Z., Z. Zhang, X. Sun, W. Wan, L. Cui, X. Zhang, D. Zhong, G. Yan and L. Cui. 2007. Molecular analysis of chloroquine resistance in Plasmodium falciparum in Yunnan province, China. Tropical Medicine and International Health 12: 1051-1060. Pai A., S. Feil and G. Yan. 2007. Variation in polyandry and its fitness consequences among populations of the red flour beetle, Tribolium castaneum. Evolutionary Ecology 21: 687-702. Obbard D. J., Y. M. Linton, Jiggins, F. M., Yan G. and T.J. Little. 2007. Population genetics of Plasmodium resistance genes in Anopheles gambiae: no evidence for strong selection. Molecular Ecology 16: 2497-3510. Garros C., N. Ngungi, A.E. Githeko, N. Tuno, G. Yan. 2008. Gut content identification of larvae of the Anopheles gambiae complex in western Kenya using a barcoding approach. Molecular Ecology Resources 8:512-518. Li C., M. T. Marrelli, G. Yan and M. 2008. Jacobs-Lorena. Fitness of transgenic Anopheles stephensi mosquitoes expressing the SM1 peptide under the control of a vitellogenin promoter. Journal of Heredity 99: 275-282. Zhong D., Y. Afrane, A. K. Githeko, L. Cui, D. M. Menge and G. Yan. 2008. Molecular epidemiology of drug-resistant malaria in western Kenya Highlands. BMC Infectious Diseases 2008, 8:105 Afrane Y. A., T. J. Little, B. W. Lawson, A. K. Githeko and G. Yan. 2008. Deforestation and Vectorial Capacity of Anopheles gambiae Giles Mosquitoes in Malaria Transmission, Kenya. Emerging Infectious Diseases 14:1533-1538. Obbard D. J., D. M. Callister, F. M. Jiggins, D. C. Soares, G. Yan, and T. J. Little. 2008. The evolution of TEP1, an exceptionally polymorphic immunity gene in Anopheles gambiae. BMC Evolutionary Biology 2008, 8:274 |
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| Grant | Funded by NIH and NSF | |
| Link to this profile | http://www.faculty.uci.edu/profile.cfm?faculty_id=5307 | |
| Last updated | 11/10/2009 | |