Ayala Diego auteur aut IRD Guerrero R. F. auteur aut IRD Kirkpatrick M. auteur aut IRD text journalArticle eng text/pdf born digital access Chromosome inversions have long been thought to be involved in speciation and local adaptation. We have little quantitative information, however, about the effects that inversion polymorphisms have on reproductive isolation and viability. Here we provide the first estimates from any organism for the total amount of reproductive isolation associated with an inversion segregating in natural populations. We sampled chromosomes from 751 mosquitoes of the malaria vector Anopheles funestus along a 1421 km transect in Cameroon that traverses savannah, highland, and rainforest ecological zones. We then developed a series of population genetic models that account for selection, migration, and assortative mating, and fit the models to the data using likelihood. Results from the best-fit models suggest there is strong local adaptation, with relative viabilities of homozygotes ranging from 25% to 130% compared to heterozygotes. Viabilities vary qualitatively between regions: the inversion is underdominant in the savannah, whereas in the highlands it is overdominant. The inversion is also implicated in strong assortative mating. In the savannah, the two homozygote forms show 92% reproductive isolation, suggesting that this one inversion can generate most of the genetic barriers needed for speciation. specialized Anopheles assortative mating selection postzygotic prezygotic speciation CAMEROUN 052 020 67 4 946-958 2013 0014-3820 https://www.documentation.ird.fr/hor/fdi:010060813 10.1111/j.1558-5646.2012.01836.x 0014-3820 [F B010060813] https://www.documentation.ird.fr/hor/fdi:010060813 https://www.documentation.ird.fr/intranet/publi/2013/05/010060813.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2013-05-31 2024-03-07 fdi:010060813 fre