Should 4th District Judge Cullen Y. Christensen allow DNA identification test results in Joe Jiron's murder trial, it will mark the first time DNA matching is used in a Utah criminal case.
DNA matching has been used for several years to determine biological fathers. However, investigators have only used the technique in forensic science for the past few years.Charlotte Wood, a national expert on DNA identification who is testifying in the Jiron trial, said she has testified on DNA matching 35 times in 11 states. DNA matching is now being used by prosecutors to connect suspects to crime scenes the same way fingerprints are used.
"With the exception of twins, each individual's DNA is unique to them," Wood said. "If DNA in a suspect's blood matches DNA taken from a crime scene, then it's virtually guaranteed that the suspect was there."
DNA is the chemical on chromosomes that determines an organism's makeup and traits. DNA is in all cells except red blood cells, Wood said. All tissue, hair, blood and all bodily fluids contain DNA. If investigators find evidence at a crime scene that contains DNA, they can see if it matches a suspect's DNA.
In humans, 99 percent of DNA is the same. The remaining 1 percent that is unique to each person is what gives them different traits. However, part of the unique DNA has no function and that is the part that experts try to match. Technicians can break down DNA into small sections and, by making the sections radioactive, can produce an image of the DNA's makeup on photographic paper. Experts then match the images from DNA found at the crime scene to DNA obtained from the suspect.
DNA matching has a benefit that fingerprinting does not have - a longer life. Experts have taken DNA from evidence that was more than 10 years old, Wood said.
Utah prosecutors are anxiously awaiting Christensen's ruling because DNA matching is expected to become common evidence in Utah's courtrooms. The Utah Department of Public Safety recently opened a DNA lab and is encouraging prosecutors to take advantage of the new technology.
"We hope that it will be accepted in the court system and will be utilized by the prosecution and defense in figuring out who the culprit is," said Pilar Shortsleve, criminologist at the state crime lab. "DNA allows a suspect to be exonerated from a crime as well as be included."
Utah prosecutors have not used DNA matching before because of the costs and time involved in getting results back. It takes about seven months to get results back from the Federal Bureau of Investigation's DNA lab. Utah County sent evidence from Jiron's case to Cellmark Diagnostics, a private DNA lab in Maryland, at the cost of about $10,000. The technique has only been used when investigators have little evidence connecting suspects to a crime scene.
"With the state's new DNA lab, I think investigators will start using DNA testing a lot more," said Utah County sheriff's detective Scott Carter.
The reliability of DNA identification is the issue facing judges. However, when the testing is done properly and safeguards are taken to eliminate human error, the identification technique is more reliable than fingerprinting, Wood said.