A progressive type of testing that separates male DNA profiles from those of females is helping the Houston’s Harris County Medical Examiner’s Office start solving sexual assaults and other crimes that previously yielded inconclusive results, the Houston Chronicle reports. 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 has already yielded positive results in 20 sexual assault cases. Medical Examiner Luis Sanchez calls the new test a “byproduct of cutting-edge science.” Known as Y-chromosome detection analysis, the test extends the time that evidence may be collected after a sexual assault from the typical 48 hours up to 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. Among the cases that have yielded results is that of a 9-year-old girl who reported a male relative molested her while she slept. No one else witnessed the crime, and no semen was recovered. Traditional DNA tests yielded inconclusive results. The new technology turned up a partial DNA profile on swabs and portions of the girl’s clothing that matched the suspect’s.