It takes less than a nanogram (or less than one billionth of the mass of a penny) of your dried saliva for scientists to construct a digital portrait that bears an uncanny resemblance to your very own face. For proof look to Hong Kong, where a recent ad campaign takes advantage of phenotyping, the prediction of physical appearance based on bits of DNA, to publicly shame people who have littered.
If you walk around the city, you'll notice portraits of people who look both scarily realistic and yet totally fake. These techno-futuristic most-wanted signs are the work of ad agency Ogilvy for nonprofit Hong Kong Cleanup, which is attempting to curb Hong Kong's trash problem with the threat of high-tech scarlet lettering. It's an awful lot like the Stranger Visions project from artist Heather Dewey-Hagborg, who used a similar technique a couple years back to construct sculptural faces as a way to provoke conversation around what we should be using these biological tools for.