Massive introgression drives species radiation at the range limit of Anopheles gambiae
Vicente JL., Clarkson CS., Caputo B., Gomes B., Pombi M., Sousa CA., Antao T., Dinis J., Bottà G., Mancini E., Petrarca V., Mead D., Drury E., Stalker J., Miles A., Kwiatkowski DP., Donnelly MJ., Rodrigues A., Torre AD., Weetman D., Pinto J.
AbstractImpacts of introgressive hybridisation may range from genomic erosion and species collapse to rapid adaptation and speciation but opportunities to study these dynamics are rare. We investigated the extent, causes and consequences of a hybrid zone betweenAnopheles coluzziiandAnopheles gambiaein Guinea-Bissau, where high hybridisation rates appear to be stable at least since the 1990s.Anopheles gambiaewas genetically partitioned into inland and coastal subpopulations, separated by a central region dominated byA. coluzzii. Surprisingly, whole genome sequencing revealed that the coastal region harbours a hybrid form characterised by anA. gambiae-like sex chromosome and massive introgression ofA. coluzziiautosomal alleles. Local selection on chromosomal inversions may play a role in this process, suggesting potential for spatiotemporal stability of the coastal hybrid form and providing resilience against introgression of medically-important loci and traits, found to be more prevalent in inlandA. gambiae.