Magdalena ZarowieckiYvonne Marie LintonRory J. PostMichael J. BangsPe Than HtunThaung HlaingChang Moh SengVisut BaimaiTrung Ho DingTho SochanthaCatherine WaltonWellcome Trust Sanger InstituteSmithsonian InstitutionWalter Reed Army Institute of ResearchLiverpool John Moores UniversityPublic Health and Malaria Control Department, PapuaDepartment of Health Ministry of HealthOrganisation Mondiale de la SanteMahidol UniversityNational Institute of Malariology, Parasitology and Entomology HanoiNational Center for Parasitology, Entomology and Malaria ControlUniversity of Manchester2018-11-092018-11-092014-01-01Molecular Ecology. Vol.23, No.10 (2014), 2573-25891365294X096210832-s2.0-84900818646https://repository.li.mahidol.ac.th/handle/20.500.14594/33169Southeast Asia harbours abundant biodiversity, hypothesized to have been generated by Pliocene and Pleistocene climatic and environmental change. Vicariance between the island of Borneo, the remaining Indonesian archipelago and mainland Southeast Asia caused by elevated sea levels during interglacial periods has been proposed to lead to diversification in the littoral zone mosquito Anopheles (Cellia) sundaicus (Rodenwaldt) sensu lato. To test this biogeographical hypothesis, we inferred the population history and assessed gene flow of A. sundaicus s.l. sampled from 18 populations across its pan-Asian species range, using sequences from mitochondrial cytochrome c oxidase subunit 1 (CO1), the internal transcribed spacer 2 (ITS2) and the mannose phosphate isomerase (Mpi) gene. A hypothesis of ecological speciation for A. sundaicus involving divergent adaptation to brackish and freshwater larval habitats was also previously proposed, based on a deficiency of heterozygotes for Mpi allozyme alleles in sympatry. This hypothesis was not supported by Mpi sequence data, which exhibited no fixed differences between brackish and freshwater larval habitats. Mpi and CO1 supported the presence of up to eight genetically distinct population groupings. Counter to the hypothesis of three allopatric species, divergence was often no greater between Borneo, Sumatra/Java and the Southeast Asian mainland than it was between genetic groupings within these landmasses. An isolation-with-migration (IM) model indicates recurrent gene flow between the current major landmasses. Such gene flow would have been possible during glacial periods when the current landmasses merged, presenting opportunities for dispersal along expanding and contracting coastlines. Consequently, Pleistocene climatic variation has proved a homogenizing, rather than diversifying, force for A. sundaicus diversity. © 2014 John Wiley & Sons Ltd.Mahidol UniversityAgricultural and Biological SciencesBiochemistry, Genetics and Molecular BiologyArticleSCOPUS10.1111/mec.12761