Recurrent specialization on a toxic fruit in an island Drosophila population
Résumé
Significance Host plant specialization is a major cause of diversification in insects. The specialization of the fly Drosophila sechellia on the toxic fruits of noni has been a source of great scientific value, but selection is old enough that genetic variation does not seem useful in mapping the causative genes. On the island of Mayotte, we discovered a population of the related species Drosophila yakuba that is strongly associated with noni compared with generalist mainland populations. We then leveraged genomic variation to reconstruct the recent divergence history of this population and identify the potential targets of selection. Our top candidates included genes that confer tolerance to noni's toxin in D. sechellia . These findings establish a new model for recurrent ecological specialization.