SNP Genotyping Defines Complex Gene-Flow Boundaries Among African Malaria Vector Mosquitoes

Broad Institute, Cambridge, MA 02142, USA.
Science (Impact Factor: 33.61). 10/2010; 330(6003):514-7. DOI: 10.1126/science.1193036
Source: PubMed


Mosquitoes in the Anopheles gambiae complex show rapid ecological and behavioral diversification, traits that promote malaria transmission and complicate vector
control efforts. A high-density, genome-wide mosquito SNP-genotyping array allowed mapping of genomic differentiation between
populations and species that exhibit varying levels of reproductive isolation. Regions near centromeres or within polymorphic
inversions exhibited the greatest genetic divergence, but divergence was also observed elsewhere in the genomes. Signals of
natural selection within populations were overrepresented among genomic regions that are differentiated between populations,
implying that differentiation is often driven by population-specific selective events. Complex genomic differentiation among
speciating vector mosquito populations implies that tools for genome-wide monitoring of population structure will prove useful
for the advancement of malaria eradication.

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Available from: Marc A T Muskavitch
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    • "Anopheles mosquitoes are found on all continents, with the exception of Antarctica, and represent more than 500 species that are often organized in sibling species complexes. The African Anopheles gambiae complex has been extensively studied and revealed a complex history of ancient introgression, recent speciation and ongoing gene flow among sibling species (Lawniczak et al. 2010; Neafsey et al. 2010, 2015; Riehle et al. 2011; Lee et al. 2013; Clarkson et al. 2014; Weetman et al. 2014; Fontaine et al. 2015). Unfortunately, most non-African Anopheles species have been much less studied and remained poorly understood. "
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    ABSTRACT: Anopheles mosquitoes are the vectors of several human diseases including malaria. In many malaria endemic areas, several species of Anopheles coexist, sometimes in the form of related sibling species that are morphologically indistinguishable. Determining the size and organization of Anopheles populations, and possible on-going gene flow among them is important for malaria control and, in particular, for monitoring the spread of insecticide resistance alleles. However, these parameters have been difficult to evaluate in most Anopheles species due to the paucity of genetic data available. Here we assess the extent of contemporary gene flow and historical variations in population size by sequencing and de novo assembling the genomes of wild-caught mosquitoes from four species of the Anopheles punctulatus group of Papua New Guinea. Our analysis of more than 50 Mb of orthologous DNA sequences revealed no evidence of contemporary gene flow among these mosquitoes. In addition, investigation of the demography of two of the Anopheles punctulatus species revealed distinct population histories. Overall, our analyses suggest that, despite their similarities in morphology, behavior and ecology, contemporary sympatric populations of Anopheles punctulatus are evolving independently. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Full-text · Article · Feb 2015 · Molecular Ecology
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    • "gambiae Gillies 'BAMAKO' chromosomal form in Mali (Coluzzi et al. 1985, 2002; Tour e et al. 1998), which is characterized by locally selected adaptive karyotypes making it fit to a peculiar larval habitat (i.e. laterite rock pools) and eventually leading to formation of reproductive barriers isolating it from sympatric 'SAVANNA' chromosomal form populations (Manoukis et al. 2008; Neafsey et al. 2010; Lee et al. 2013b). We analysed An. coluzzii and An. "
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    ABSTRACT: The Anopheles gambiae complex of mosquitoes includes malaria vectors at different stages of speciation, whose study enables a better understanding of how adaptation to divergent environmental conditions leads to evolution of reproductive isolation. We investigated the population genetic structure of closely-related sympatric taxa that have recently been proposed as separate species (An. coluzzii and An. gambiae), sampled from diverse habitats along the Gambia River in West Africa. We characterised putatively neutral microsatellite loci as well as chromosomal inversion polymorphisms known to be associated with ecological adaptation. The results revealed strong ecologically-associated population subdivisions within both species. Microsatellite loci on chromosome-3L revealed clear differentiation between coastal and inland populations, which in An. coluzzii is reinforced by a unusual inversion polymorphism pattern, supporting the hypothesis of genetic divergence driven by adaptation to the coastal habitat. A strong reduction of gene-flow was observed between An. gambiae populations west and east of an extensively rice-cultivated region apparently colonized exclusively by An. coluzzii. Notably, this ‘intra-specific’ differentiation is higher than that observed between the two species and involves also the centromeric region of chromosome-X which has previously been considered a marker of speciation within this complex, possibly suggesting that the two populations may be at an advanced stage of differentiation triggered by human-made habitat fragmentation. These results confirm ongoing ecological speciation within these most important Afro-tropical malaria vectors and raise new questions on the possible effect of this process in malaria transmission.This article is protected by copyright. All rights reserved.
    Full-text · Article · Jul 2014 · Molecular Ecology
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    • "Complex gene flow boundaries have already been found among the An. gambiae chromosomal forms (della Torre et al. 1997; Turner et al. 2005; Slotman et al. 2006; Lawniczak et al. 2010; Neafsey et al. 2010). For vector control, this may mean that there is a potential for transgenic elements or biocide resistance to spread across species boundaries (Djogbenou et al. 2008), so future monitoring programmes will perhaps need to extend monitoring of vectors across species boundaries in species complexes. "

    Full-text · Dataset · May 2014
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