Heather Dewey-Hagborg is an artist who creates portraits of strangers based on DNA extracted from random rubbish.

The project is meant to raise awareness of genetic surveillance, Dewey-Hagborg says.

"We should be concerned because we don't know, yet, how our DNA might be used against us in the future," she says.

Genetic artefacts such as cigarette butts and chewing gum yield enough DNA to determine one's ancestry, eye colour, and whether or not the person has a tendency to be overweight.

The BBC visited Dewey-Hagborg on the streets of New York.

Produced by the BBC's Jane O'Brien, Dave Hopper and Ilya Shnitser