Believe it or not, police have a real problem with identifying suspects who are identical twins -- unless you're willing to spend a month sequencing genes, DNA samples are all but useless. They may be far more effective in the future, though, as British researchers have developed a technique that melts DNA to identify what few differences exist. The team has determined that heating genes will break hydrogen bonds that form due to a person's environment and habits. Unless the twins live eerily similar lives, those bonds will snap at different temperature points and quickly identify who's who.
The technique requires a relatively large sample, so it wouldn't work if there's just a scant amount of DNA at a crime scene. However, it should only take a few hours to get a result. So long as the technology reaches the field, law enforcement would have a relatively easy time determining the evil twin (and exonerating the good one, of course) while the accusations are still fresh.
[Image credit: AP Photo/M. Spencer Green]