@article{fdi:010050151,
  title = {{M}olecular evolution of immune genes in the malaria mosquito {A}nopheles gambiae},
  author = {{L}ehmann, {T}. and {H}ume, {J}.{C}.{C}. and {L}icht, {M}. and {B}urns, {C}.{S}. and {W}ollenberg, {K}. and {S}imard, {F}r{\'e}d{\'e}ric and {R}ibeiro, {J}.{M}.{C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground. {A}s pathogens that circumvent the host immune response are favoured by selection, so are host alleles that reduce parasite load. {S}uch evolutionary processes leave their signature on the genes involved. {D}eciphering modes of selection operating on immune genes might reveal the nature of host-pathogen interactions and factors that govern susceptibility in host populations. {S}uch understanding would have important public health implications.{M}ethodology/{F}indings. {W}e analyzed polymorphisms in four mosquito immune genes ({SP}14{D}1, {GNBP}, defensin, and gambicin) to decipher selection effects, presumably mediated by pathogens. {U}sing samples of {A}nopheles arabiensis, {A}n. quadriannulatus and four {A}n. gambiae populations, as well as published sequences from other {C}ulicidae, we contrasted patterns of polymorphisms between different functional units of the same gene within and between populations. {O}ur results revealed selection signatures operating on different time scales. {A}t the most recent time scale, within-population diversity revealed purifying selection. {B}etween populations and between species variation revealed reduced differentiation ({GNBP} and gambicin) at coding vs. noncoding- regions, consistent with balancing selection. {M}c{D}onald-{K}reitman tests between {A}n. quadriannulatus and both sibling species revealed higher fixation rate of synonymous than nonsynonymous substitutions ({GNBP}) in accordance with frequency dependent balancing selection. {A}t the longest time scale (>100 my), {PAML} analysis using distant {C}ulicid taxa revealed positive selection at one codon in gambicin. {P}atterns of genetic variation were independent of exposure to human pathogens.{S}ignificance and {C}onclusions. {P}urifying selection is the most common form of selection operating on immune genes as it was detected on a contemporary time scale on all genes. {S}election for "hypervariability" was not detected, but negative balancing selection, detected at a recent evolutionary time scale between sibling species may be rather common. {D}etection of positive selection at the deepest evolutionary time scale suggests that it occurs infrequently, possibly in association with speciation events. {O}ur results provided no evidence to support the hypothesis that selection was mediated by pathogens that are transmitted to humans.},
  keywords = {{PALUDISME} ; {VECTEUR} ; {MOUSTIQUE} ; {SELECTION} ; {GENE} ; {IMMUNITE} ; {RELATION} {HOTE} {PARASITE} ; {SENSIBILITE} {RESISTANCE} ; {EVOLUTION} ; {KENYA} ; {NIGERIA} ; {SENEGAL} ; {ZIMBABWE} ; {ASEMBO} ; {JEGO} ; {GWAMLAR} ; {BERKEDJI}},
  booktitle = {},
  journal = {{PL}o{S} {O}ne},
  volume = {4},
  numero = {2},
  pages = {e4549},
  ISSN = {1932-6203},
  year = {2009},
  DOI = {10.1371/journal.pone.0004549},
  URL = {https://www.documentation.ird.fr/hor/fdi:010050151},
}