As well as carrying genetic instructions, it turns out DNA makes a handy weapon too. As a last-ditch defence against invading microbes, immune cells spew out sticky nets of their DNA.
Normally, immune cells called neutrophils kill microbes by gobbling them up or releasing toxic chemicals. But when all else fails, they disgorge complex nets of their DNA, studded with antimicrobial compounds. The nets can span small blood vessels, ensnaring and killing bacteria.