Forensic genetics: DNA fingerprinting

DNA Fingerprinting is everywhere! You probably can’t remember a time when DNA and crime solving didn’t go together. But the technology to do “DNA fingerprinting“ didn’t even exist until the early 1980’s! This is when scientists found out they could see differences in people’s DNA. It only took police a few years to start using DNA for solving crimes. In 1987 the first criminal was caught using DNA evidence. On the other hand, in 1989 DNA fingerprinting was used for the first time to prove that someone was actually innocent of a crime. Today the Innocence Project in New York works to help inmates get access to DNA evidence to hopefully free more innocent people. If you turn on your television any night of the week you can see how important DNA testing has become. From crime dramas to real life crimes on the news, DNA evidence is everywhere! There’s a lot more that DNA testing can be used for though. The same technology that can catch the bad guy can be used to solve other mysteries. After we talk about how DNA fingerprinting works, we’ll look at three real-life mysteries that people are solving using DNA. So how does it work? A “DNA fingerprint“ is kind of like a regular fingerprint. You are born with it, it is unique to you (unless you have an identical twin!), and you can leave it behind wherever you go. But unlike a fingerprint from your hand, your DNA fingerprint can’t be found by just “dusting for prints“ like they do on detective shows. To find a DNA fingerprint, a scientist has to first take the DNA out of the nucleus of a cell. The cell that is used to get a DNA fingerprint can be a skin cell, a hair root cell, or even a cheek cell that gets washed out of your mouth in your spit. This is because your unique DNA is the same in all of your cells. So what do they do once they take the DNA out of the cell? Well, the goal is to analyze the DNA in a way that shows scientists the tiny differences in the DNA of different people. In the past, scientists used a technique called RFLP (Restriction Fragment Length Polymorphism). RFLP analysis needs lots of DNA, but sometimes only a little is left behind at a crime scene. So scientists found a way to use less DNA. They worked out a method called microsatellite analysis. But scientists want to find ways to use even less DNA. They also want to find a way to speed up the process. On TV the investigators get the DNA answers by the end of the show, but in real life there are so many samples waiting to be tested that labs can’t handle them all. The wave of the future is something called “lab-on-a-chip.“ It will be a credit card sized machine that you could load a tiny sample into on the spot – you wouldn’t have to wait until you got back to the lab. Lab-on-a-chip would use tiny tubes and pumps to perform all the steps normally done by hand by scientists. It would take the DNA out of a sample, make lots of copies of the DNA, and analyze the fingerprint. It would do all this at a fraction of the cost and in a fraction of the time that current methods use. #DNA #RFLP #RFLPAnalysis #microsatelliteAnalysis #DNAFingerprint #Genetics #forensicGenetics