A progressive type of testing that separates male DNA profiles from those of females is helping the Harris County Medical Examiner's Office start solving sexual assaults and other crimes that previously yielded inconclusive results. The new male-specific DNA test zeroes in on minute amounts of biological evidence, such as saliva, skin cells or a trace of semen.
The technology, which the office began using in June, has already yielded positive results in 20 sexual assault cases reviewed by the institution's forensic biology laboratory. Harris County Chief Medical Examiner Luis Sanchez calls the new test a “byproduct of cutting-edge science.”
Known as Y-chromosome detection analysis, the test has other benefits as well. It extends the time that evidence may be collected after a sexual assault from the typical 48 hours all the way up to 96 hours — or some experts say, a maximum of 120 hours.
In a rape case with multiple perpetrators, the male-specific test also will determine the number of men who participated in the attack.