Jul 10, 2008 11:12 pm US/Central
Good Question: What Does Our DNA Say About Us?
(WCCO)
On crime shows like CSI, DNA is the key to everything. Advances in technology just helped clear JonBenet Ramsey's parents of suspicion they killed their daughter. We all know that real crime labs don't look like the ones on TV, but what about real DNA?
"The information that we look at in the DNA does not give us a lot of information," said Kris Deters, acting supervisor of the Nuclear DNA section at the Minnesota Bureau of Criminal Apprehension Crime Lab.
Deters said that's because in a crime lab, investigators are zeroing in on a tiny portion of genetic code.
"Because we just look at such a small area in the DNA, we don't have all of the information that our DNA actually can tells us," she said. "We just look at a small portion of that."
DNA in the "everyday crime lab" does not tell race, age or characteristics like hair and eye color, according to Deters. However, private laboratories are experimenting with DNA tests that will give clues on all of those descriptors.
"We expect that will be coming down to us as the science advances," explained Deters.
Her lab has to process evidence to a degree of certainty that will hold up in court. The private labs can help investigators on the front end of things, but they don't have the level of scientific certainty commonly accepted by courts.
In general, right now DNA doesn't help find a bad guy, but a DNA match can sink or save a suspect.
"Each person has a unique DNA, other than if they're identical twins," said Deters.
The biggest development is in where investigators can find DNA.
"Even as much as five, ten years ago we never did cigarette butts for example. We didn't know if we had enough DNA to get a result," said Deters. "Now we're doing things like cigarette butts, pop can bottles, DNA that's left behind on surfaces or clothing items."
They call it a "Touch DNA" test. In Minnesota, investigators have been using that for two years. It doesn't require blood or hair, instead, a sample of a skin cell simply touching something else is enough.
"To be able to even think about getting DNA from somebody just by them wearing a clothing item is very exciting," said Deters. For example, investigators will check the armpit of a shirt to look for DNA.
Minnesota's BCA Crime Lab has 30 investigators in the DNA area as part of a staff of 100 or so.
The strangest recent place Deters found DNA was on a piece of food.
"I think we got it off of a piece of pizza. And so somebody had taken a bite and left behind the rest of the pizza, and we got their saliva on the pizza," she said.
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