title: Within-host speciation of malaria parasites.
abstract: BACKGROUND
  Sympatric speciation-the divergence of populations into new species in absence of geographic barriers to hybridization-is the most debated mode of diversification of life forms. Parasitic organisms are prominent models for sympatric speciation, because they may colonise new hosts within the same geographic area and diverge through host specialization. However, it has been argued that this mode of parasite divergence is not strict sympatric speciation, because host shifts likely cause the sudden effective isolation of parasites, particularly if these are transmitted by vectors and therefore cannot select their hosts. Strict sympatric speciation would involve parasite lineages diverging within a single host species, without any population subdivision.
  
  
  RESULTS
  Here we report a case of extraordinary divergence of sympatric, ecologically distinct, and reproductively isolated malaria parasites within a single avian host species, which apparently occurred without historical or extant subdivision of parasite or host populations.
  
  
  CONCLUSIONS
  This discovery of within-host speciation changes our current view on the diversification potential of malaria parasites, because neither geographic isolation of host populations nor colonization of new host species are any longer necessary conditions to the formation of new parasite species.
authors.affiliation: Department of Animal Ecology, Lund University, Lund, Sweden. jperez@bio.ucm.es
authors.forename: Javier
authors.initials: J
authors.lastname: Pérez-Tris
authors.forename: Olof
authors.initials: O
authors.lastname: Hellgren
authors.forename: Asta
authors.initials: A
authors.lastname: Krizanauskiene
authors.forename: Jonas
authors.initials: J
authors.lastname: Waldenström
authors.forename: Jean
authors.initials: J
authors.lastname: Secondi
authors.forename: Camille
authors.initials: C
authors.lastname: Bonneaud
authors.forename: Jon
authors.initials: J
authors.lastname: Fjeldså
authors.forename: Dennis
authors.initials: D
authors.lastname: Hasselquist
authors.forename: Staffan
authors.initials: S
authors.lastname: Bensch
mesh_terms: D000349:Africa; D025041:Animal Migration; D000818:Animals; D001483:Base Sequence; D002519:Ceratopogonidae / Q000469:parasitology; D045303:Cytochromes b / Q000235:genetics; D019353:Endemic Diseases / Q000662:veterinary; D005060:Europe; D053476:Extinction, Biological; D051456:Gene Flow; D050259:Genes, Mitochondrial; D049810:Genetic Speciation; D016787:Haemosporida / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D006790:Host-Parasite Interactions; D007303:Insect Vectors / Q000469:parasitology; D008289:Malaria, Avian / Q000469:parasitology*; D008969:Molecular Sequence Data; D046109:Passeriformes / Q000469:parasitology; D010802:Phylogeny; D010961:Plasmodium / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D015800:Protozoan Proteins / Q000235:genetics; D020308:Songbirds / Q000469:parasitology*; D013045:Species Specificity; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
chemical_list: D015800:Protozoan Proteins; D045303:Cytochromes b; D013762:Tetrahydrofolate Dehydrogenase