Valerian
PIERREJOSEPH REDOUTE/GETTY (2)
Madagascar periwinkle
CRAIG CUTLER/TRUNK ARCHIVE
HUMANS AREN’T THE ONLY ORGANISMS WITH FLEXIBLE GENES. Anything that reproduces contains a blueprint for making more of itself. And all DNA is susceptible to outside influence: The environment in which it lives can force dormant genes into action or new traits to appear. Stressful situations—changes in climate, temperature or predators, for example—are particularly good at eliciting genetic change.