North Louisiana Crime Lab adopts advanced DNA software to help solve complex cases
SHREVEPORT, La. — The North Louisiana Crime Laboratory in Shreveport has begun using new DNA analysis software designed to help forensic scientists interpret complex or damaged DNA evidence that previously may have been too difficult to analyze.
North Louisiana Crime Lab in Shreveport.
SHREVEPORT, La. — The North Louisiana Crime Laboratory in Shreveport has begun using new DNA analysis software designed to help forensic scientists interpret complex or damaged DNA evidence that previously may have been too difficult to analyze.
The laboratory is the 99th forensic lab in the United States to adopt STRmix, a probabilistic genotyping software used to analyze mixed DNA samples from crime scenes. The software has been used in more than 700,000 criminal cases worldwide since its introduction in 2012, according to a laboratory news release.
Officials said the technology has been especially helpful in violent crime, sexual assault and cold case investigations by producing usable DNA results from evidence that was once considered inconclusive.
The North Louisiana Crime Laboratory provides forensic science services to law enforcement agencies in the northern 29 parishes of Louisiana. Its services include DNA analysis, drug chemistry, firearms examination, fire debris analysis and forensic toxicology. The agency operates laboratories in Shreveport and Alexandria and an evidence hub in Ouachita Parish.
Jessica Esparza, the laboratory's DNA technical leader, said the agency is also the first laboratory in the United States to validate the VeriFiler Plus PCR amplification kit for use with STRmix.
"Even though we are the 99th U.S. laboratory to begin using this software, we are the first in this country to validate the VeriFiler Plus PCR amplification kit with STRmix, allowing us to utilize more information within the DNA profile to deconvolute complex mixtures," Esparza said in the news release. "This advancement gives us the ability to interpret complex mixtures that were previously uninterpretable using binary methods."
Unlike older DNA analysis methods that rely on fixed thresholds and manual interpretation, STRmix uses statistical modeling to evaluate hundreds of thousands of possible DNA profile combinations. When investigators have a DNA sample from a person of interest, the software calculates a likelihood ratio that measures how strongly the DNA evidence supports a possible match, the news release states.
More than 120 forensic laboratories around the world now use STRmix, including facilities in the United States, Canada, the United Kingdom, Europe, Asia, the Middle East, the Caribbean, Australia and New Zealand.