Flossing, Zika and asexual evolution

Flossing teeth: we all do it—or think we should do it—but is it scientific? Numerous scientific studies say flossing your teeth won't prevent tooth decay, and mouthwash may be just as good or better.Asexual organisms (that got your attention) are subject to the Meselson effect, in which genes on separate chromosomes evolve separately. And this could eventually cause Trypanosoma brucei gambiense—the parasite that causes African sleeping sickness—to go extinct.Speaking of diseases to worry about, we talk to virologist Ian Mackay about the mosquito-borne global health emergency, the Zika virus. Is it time to panic? Eh...