The evolution and dispersal of the invasive malaria vector, Anopheles stephensi : a genomic approach.

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dc.contributor.advisorCarter, Tamar.
dc.creatorSamake, Jeanne N., 1985-
dc.date.accessioned2024-07-17T14:03:10Z
dc.date.available2024-07-17T14:03:10Z
dc.date.created2023-08
dc.date.issued2023-08
dc.date.submittedAugust 2023
dc.date.updated2024-07-17T14:03:10Z
dc.description.abstractAnopheles stephensi, a primary malaria vector in South Asia and parts of the Middle East, has been detected in countries in Africa, Yemen, and Sri Lanka. In Africa, the detection of An. stephensi has been associated with malaria outbreaks in the Horn of Africa region, threatening global efforts for malaria reduction and elimination. The spread of An. stephensi, with a coincident increase in malaria disease burden, led the World Health Organization to issue a “vector alert” in 2019, calling for targeted An. stephensi control and increasing surveillance in Africa and neighboring malaria-endemic regions. To combat this invasive disease vector, understanding the history of introduction(s), establishment(s), and potential source populations is essential to predict future expansions and establish where they may be effectively controlled. To this end, this dissertation involved the application of genetic and genomic approaches to characterize invasive An. stephensi populations in the HoA and Yemen. First, using a DNA-targeted approach, we investigated the evolution of the pyrethroid resistance kdr mutation in the invasive An. stephensi from Ethiopia for the first time. Our finding showed that kdr target site resistance is not the primary insecticide resistance mechanism. Secondly, we assayed 1,680 neutral SNP markers of the HoA An. stephensi, from which principal component and ancestral genetic analyses revealed an isolation-by-distance dispersal pattern with one of the major hubs corresponding to a recent malaria site in Ethiopia. Thirdly, we assayed 2,270 neutral SNP markers of the Yemeni An. stephensi from which pairwise Fst and genetic network revealed the dispersal patterns with Aden An. stephensi as a source population within Yemen. Comparative genomic analyses showed that the Yemeni An. stephensi is younger than Somaliland, northeastern Ethiopia, and east central Ethiopia An. stephensi. Lastly, using entomological and genomic data, we detected and molecularly confirmed the presence of the invasive An. stephensi in an eastern Ethiopian town for the first time. We then uncovered the source population that founded the new An. stephensi colony. Overall, this dissertation shows how genomic data can provide finer-scale population structure to uncover dispersal patterns and source populations and help elucidate evolutionary relationships between invasive An. stephensi populations.
dc.format.mimetypeapplication/pdf
dc.identifier.uri
dc.identifier.urihttps://hdl.handle.net/2104/12806
dc.language.isoEnglish
dc.rights.accessrightsNo access – contact librarywebmaster@baylor.edu
dc.titleThe evolution and dispersal of the invasive malaria vector, Anopheles stephensi : a genomic approach.
dc.typeThesis
dc.type.materialtext
local.embargo.lift2025-08-01
local.embargo.terms2025-08-01
thesis.degree.departmentBaylor University. Dept. of Biology.
thesis.degree.grantorBaylor University
thesis.degree.namePh.D.
thesis.degree.programBiology
thesis.degree.schoolBaylor University

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