i DuNnA know!

saturday afternoon, i was half-watching some bad early 90’s movie of the week which starred tracy lords and the chick from ‘wings’ (who shall from now on be referred to as ‘betty’ as i don’t remember the name of her character or her real name) in which betty befriends tracy, tracy develops a condition which requirs surgery, tracy has no insurance, betty suggests they pretend to be each other so tracy can get her surgery under betty’s insurance, tracy mysteriously dies during said surgery, everyone thinks betty is dead, betty spends the rest of the movie living tracy’s life and trying to figure out what went wrong (i think — i didn’t watch to the end).
the first thing i thought of when the funeral home director tells betty (the real betty) that she (tracy, who they all think is betty) missed the service and the body was cremated was “why can’t they just do a dna test to prove it was actually her?”
i brought this up while playing cards saturday and the consensus seemed to be that once a human body is cremated all that is left are the base elements from which their body was composed. but i’m not so sure. i think i’ve heard that teeth don’t burn and sometimes you’re left with bits of bone left whole. couldn’t you retrieve at least one snippet of a double helix from that?