It’s true – DNA fingerprinting is an incredibly powerful tool for forensics, in part because DNA can tell us:
- if a particular person was at a crime scene (TV CSIs call this “getting a match”)
- the identity of a person whose remains can no longer be fingerprinted
- whether a suspect was a man or a woman
- whether the criminal was even human (don’t laugh – sometimes the bad guy is a literal bear!)
- whether or not people involved in an investigation are related (very handy in kidnapping cases)
Traditional fingerprints can pretty much only do the first one. BUT. Usable fingerprints are present at a lot more crime scenes than DNA. And fingerprint records have been collected for 100 years, while DNA databases are much newer. As a result, the odds of finding a matching fingerprint in the database are higher than the odds of finding a matching DNA profile.
As I tell kids during the “Mythbusting” portion of my forensics presentation, you can collect the criminal’s prints and DNA all you want, but if you haven’t collected them before, that matching thing? Just can’t happen.
According to an estimate I found while researching Forensic Science: In Pursuit of Justice, ten times more criminals are identified using fingerprints than DNA. Fingerprints can even distinguish between identical twins. That’s because fingerprint patterns are partly genetic, but partly due to chance events that occur when human fetuses are growing skin for the very first time.
One more cool fact? Everyone from Edmond Locard (groundbreaking forensic scientist) to career criminals like John Dillinger (professional bank robber), have tried burning, scraping, or otherwise rubbing out their own fingerprints. Doesn’t work. The patterns are formed by the deepest layers of skin, meaning they just grow back.
Admit it. You’re staring at your fingers, aren’t you?
Interested in booking my forensic presentation? The basic talk is one hour. If you’ve got two hours, we can do experiments. Contact me for details.
Interested in forensics? I’m offering deep discounts on bulk orders of my multi-award-winning book, Fuzzy Forensics. Perfect for classroom and library use. They also make awesome end-of-year gifts for your favourite teachers. Not available online – contact me to order.