title: Adaptive Potential of Hybridization among Malaria Vectors: Introgression at the Immune Locus TEP1 between Anopheles coluzzii and A. gambiae in 'Far-West' Africa.
abstract: "Far-West" Africa is known to be a secondary contact zone between the two major malaria vectors Anopheles coluzzii and A. gambiae. We investigated gene-flow and potentially adaptive introgression between these species along a west-to-east transect in Guinea Bissau, the putative core of this hybrid zone. To evaluate the extent and direction of gene flow, we genotyped site 702 in Intron-1 of the para Voltage-Gated Sodium Channel gene, a species-diagnostic nucleotide position throughout most of A. coluzzii and A. gambiae sympatric range. We also analyzed polymorphism in the thioester-binding domain (TED) of the innate immunity-linked thioester-containing protein 1 (TEP1) to investigate whether elevated hybridization might facilitate the exchange of variants linked to adaptive immunity and Plasmodium refractoriness. Our results confirm asymmetric introgression of genetic material from A. coluzzii to A. gambiae and disruption of linkage between the centromeric "genomic islands" of inter-specific divergence. We report that A. gambiae from the Guinean hybrid zone possesses an introgressed TEP1 resistant allelic class, found exclusively in A. coluzzii elsewhere and apparently swept to fixation in West Africa (i.e. Mali and Burkina Faso). However, no detectable fixation of this allele was found in Guinea Bissau, which may suggest that ecological pressures driving segregation between the two species in larval habitats in this region may be different from those experienced in northern and more arid parts of the species' range. Finally, our results also suggest a genetic subdivision between coastal and inland A. gambiae Guinean populations and provide clues on the importance of ecological factors in intra-specific differentiation processes.
authors.affiliation: Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, "Sapienza" Università di Roma, Rome, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Mancini
authors.affiliation: Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, "Sapienza" Università di Roma, Rome, Italy.
authors.forename: Maria Ida
authors.initials: MI
authors.lastname: Spinaci
authors.affiliation: UEI Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal; Centro de Malária e outras Doenças Tropicais Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.
authors.forename: Vasco
authors.initials: V
authors.lastname: Gordicho
authors.affiliation: Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, "Sapienza" Università di Roma, Rome, Italy.
authors.forename: Beniamino
authors.initials: B
authors.lastname: Caputo
authors.affiliation: Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, "Sapienza" Università di Roma, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Pombi
authors.affiliation: UEI Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal; Centro de Malária e outras Doenças Tropicais Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Vicente
authors.affiliation: Instituto Nacional de Saúde Pública., Bissau, Guinea Bissau.
authors.forename: João
authors.initials: J
authors.lastname: Dinis
authors.affiliation: Instituto Nacional de Saúde Pública., Bissau, Guinea Bissau.
authors.forename: Amabélia
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Dipartimento di Biologia e Biotecnologie "C. Darwin", "Sapienza" Università di Roma, Rome, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Petrarca
authors.affiliation: Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Weetman
authors.affiliation: UEI Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal; Centro de Malária e outras Doenças Tropicais Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Pinto
authors.affiliation: Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, "Sapienza" Università di Roma, Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Della Torre
mesh_terms: D056704:Adaptive Immunity; D000354:Africa, Western; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000235:genetics* / Q000254:growth & development / Q000469:parasitology; D051456:Gene Flow; D017344:Genes, Insect; D056426:Genetic Loci; D005828:Genetics, Population; D005838:Genotype; D006169:Guinea-Bissau; D006239:Haplotypes; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D015810:Linkage Disequilibrium; D008969:Molecular Sequence Data; D010961:Plasmodium / Q000502:physiology; D020641:Polymorphism, Single Nucleotide; D016415:Sequence Alignment
chemical_list: D019476:Insect Proteins; C544265:TEP1 protein, Anopheles gambiae