I’m currently writing a research paper for college on DNA evidence. Sorry, no two people share the same DNA except for identical twins. 350 billion people before coming back to another match? me thinks this guy speaks out his arse!
It's because they're not comparing the whole genome, only enough to ensure an extremely low likelihood of a false positive.
Perhaps you can comment on the following scenario, read a few years ago in a work of fiction.
A DNA sample could not be obtained from a slippery criminal who was a master at leaving false trails, falsely accusing other of his crimes anonymously, but finally busted by the simple expedient of being able to DNA profile a cooperating very close relative (e.g. parent, sibling, cousin, uncle, etc).
Is this actually possible? If nothing else, it would certainly reduce the pool of suspects dramatically.