DNA profiling (2)

So just how likely is it that your DNA profile could be confused with someone else's? The figure most commonly quoted is 1 in a billion - though exactly where that comes from is far from clear, and in any event even if it is anywhere near accurate it almost certainly relates to a "perfect world" scenario, rather than what tends to happen in practice. In reality DNA picked up at a crime scene, say, may only produce a partial profile, or one that is a mixture from several people. The UK's DNA database is run by the Home Office which last year produced a report on its use, covering the period between 2001 and 2006. This report reveals that well over a quarter of samples received from the Police during that period for potential matching resulted in more than one match being found on the database. So the reality is that false matches do occur - indeed are quite frequent. So it's far from the silver bullet that the public are encouraged to believe it is. If your DNA profile is on the database (and it could be even though you have done nothing wrong) the chance of it being confused with someone else's - on the Government's own figures - would appear to be more like 1 in a few hundred. But there's more...