Signals of Mosquito Speciation Malaria in Africa is transmitted by the mosquito species complex Anopheles gambiae . Neafsey et al. (p. 514 ) made high-resolution single-nucleotide arrays to map genetic divergence among members of the species. Differentiation between populations was observed and evidence obtained for selective sweeps within populations. Most divergence occurred within inversion regions around the centrosome and in genes associated with development, pheromone signaling, and from the X chromosome. The analysis also revealed signals of sympatric speciation occurring within similar chromosomal regions in mosquitoes from different regions in Africa. Lawniczak et al. (p. 512 ) sequenced the genomes of two molecular forms (known as M and S) of A. gambiae , which have distinctive behavioral phenotypes and appear to be speciating. This effort resolves problems arising from the apparently chimeric nature of the reference genome and confirms the observed genome-wide divergences. This kind of analysis has the potential to contribute to control programs that can adapt to population shifts in mosquito behavior arising from the selective effects of the control measures themselves.