Your DNA is your body’s most closely guarded asset. To reach it, any would-be-invaders have to get under your skin, travel through your bloodstream undetected by immune system sentries, somehow cross a cell membrane, and finally find their way into the nucleus. Most of the time, that’s a really good thing. These biological barriers prevent nasty viruses from turning your cells into disease-making factories.

Learn about your ad choices: dovetail.prx.org/ad-choices