Late Pleistocene environmental changes lead to unstable demography and population divergence of Anopheles albimanus in the northern Neotropics

We investigated the historical demography of Anopheles albimanus using mosquitoes from five countries and three different DNA regions, the mitochondrial cytochrome oxidase subunit I gene (COI), the single copy nuclear white gene and the ribosomal internal transcribed spacer two (ITS2). All the molecular markers supported the taxonomic status of a single species of An. albimanus. Furthermore, agreement between the COI and the white genes suggested a scenario of Pleistocene geographic fragmentation (i.e., population contraction) and subsequent range expansion across southern Central America.

Anopheles albimanus appears to be a single, albeit polymorphic, species that is not at mutation-drift equilibrium due to past geographic fragmentation and regional fluctuation in its effective population size. The COI gene suggests a common pattern of historical isolation, subsequent haplotype mixing, and population expansion of four mtDNA COI lineages in the late Pleistocene. Data from the white gene do not reflect the high genetic diversity of the COI, but are consistent with the scenario of late Pleistocene population expansion. Finally, lower genetic diversity by both the COI and white genes across Panama suggest that An. albimanus populations contracted, then subsequently expanded toward Nicaragua and Ecuador.Figure optionsDownload as PowerPoint slideResearch highlights
► The map shows the geographic distribution of four COI haplogroups (A, red), (B, green), (C, black) and (D, yellow) of Anopheles albimanus.
► Three population demes defined by SAMOVA are outlined: Nicaragua, Costa Rica and the Atlantic coast of western Panama; the Pacific coast of western Panama, central-eastern Panama and the Caribbean coast of Colombia; and the Pacific coast of Colombia and Ecuador.
► The SP network of eighteen white gene alleles (I–XVIII) and their geographical distributions.