DNA has four building blocks: A, C, T and G. But some bacteriophages swap A for Z, and scientists have figured out how and why they do it.
The Coronavirus Pandemic
Anxiety, depression and strokes can occur after infection, leaving experts to determine how the virus affects the brain.
From the Archives
Fishes’ flashing photonic crystals may provide inspiration for ultra-miniaturized sensors that work in a living body.