One of the most common plot threads is trying to identify or obtain for identification some DNA for comparison. I know they do this stuff at lightspeed compared to real life, but one thing I *have* wondered about is this: generally they show that they have a "database" of DNA samples to search, and I'm wondering:
1) Are there actually decent-sized databases of people's DNA already on file that could be searched that way?
2) If so, who's IN these databases, who can access them, and when/how do people get put into them in the first place?
3) Does this vary across the country? I.e., if I'm in, say, Los Angeles do I have access to databases X and Y, but not A and B, but in New York I have A, B, and X but not Y?