Guiyun Yan

Public Health

Joint appointment, Ecology & Evolutionary Biology
School of Biological Sciences

Ph.D., University of Vermont, 1994, Biology

Phone: (949) 824-0175
Fax: (949) 824-2118

University of California, Irvine
Hewitt Hall, Room 3038
Mail Code: 4050
Irvine, CA 92697

picture of Guiyun  Yan

Population biology of mosquitoes and malaria epidemiology in Africa and Southeast Asia
URLs Postdoctoral Positions Available Immediately
Ph.D. and Postdoctoral Fellowships for African Students and Scientists Available Immediately
Appointments Dr. Yan's lab members:

Dr. Meihui Wang, Postdoc fellow
Dr. Mariangela Bonizzoni, Postdoc fellow
Dr. Yaw Afrane, Postdoc fellow
Dr. Ming-chieh Lee, Postdoc fellow
Dr. Daibin Zhong, Assistant Scientist
Dr. Guofa Zhou, Associate Scientist
Thomas Gilbreath, Ph.D. Student
Rajni Boparai, Lab manager
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.
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.

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.

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.

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 8:274

Yakob L. and G. Yan. 2009. Modeling the effects of integrating habitat source reduction and insecticide treated nets for malaria control. PLoS ONE 4(9):e6921.PMID: 19742312

Bonizzonni M., Y. Afrane, F. N. Baliraine, D. A. Amenya, A. K. Githeko, and G. Yan. 2009. Genetic structure of Plasmodium falciparum populations between lowland and highland sites and antimalarial drug resistance in western Kenya. Infection, Genetics and Evolution 9: 806-12.

Baliraine F. N., Y. A. Afrane, D. A. Amenya, M. Bonizzoni, D. M. Menge, G. Zhou, D. Zhong, A. M. Vardo-Zalik, A. K. Githeko, and G. Yan. 2009. High prevalence of asymptomatic Plasmodium falciparum infections in a highland area of western Kenya: a cohort study. Journal of Infectious Diseases 200:66-74.

Li, J., Ribeiro J.M.C., and Yan G.. 2010. Allelic gene structure variations in Anopheles gambiae. PLoS ONE. 5(5): e10699. doi:10.1371/journal.pone.0010699
  Zhou G, Githeko AK, Minakawa N, Yan G. 2010. Community-wide benefits of targeted indoor residual spray for malaria control in the western Kenya highland. Malar J. 9:67.
  Yakob L, Yan G. 2010. A network population model of the dynamics and control of African malaria vectors.Trans R Soc Trop Med Hyg. 2010. 104:669-75.
  Baliraine FN, Afrane YA, Amenya DA, Bonizzoni M, Vardo-Zalik AM, Menge DM, Githeko AK, Yan G. 2010. A cohort study of Plasmodium falciparum infection dynamics in Western Kenya Highlands. BMC Infect Dis.10:283.
  Wang M, O Marinotti, AAJames, EWalker, J Githure, G Yan. 2010. The impact of aging on genome-wide patterns of gene expression in the African malaria vector Anopheles gambiae. PLoS One (in press).
  Chen L, Zhong D, Zhang D, Shi L, Zhou G, Gong M, Zhou H, Sun Y, Ma L, He J, Hong S, Zhou D, Xiong C, Chen C, Zou P, Zhu C, Yan G. 2010. Molecular ecology of pyrethroid knockdown resistance in Culex pipiens pallens mosquitoes. PLoS One 5(7):e11681.
Grant Funded by NIH and NSF
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Last updated 10/05/2010