Should you post your DNA to publicly accessible databases?

An article about how police in Wisconsin used publicly available DNA to find a killer spurred me to consider whether we have a duty to perform DNA testing on ourselves to provide police with data to track down killers and rapists in cold cases. Or does police use of our data without our permission invade our privacy?
My instincts in approaching questions like is are libertarian.
I’ve asked to be cremated. I’m thrifty, and it’s cheaper to cremate than to embalm and bury. But also, I abhor the...