Credit: Murdoch University
Researchers at Murdoch University (Australia) have made a discovery that could lead to a new weapon in the arsenal against perpetrators of sexual assault.
In a new study, Brendan Chapman and Ruby Dixon have demonstrated that bacteria can be transferred between a male and female during sexual intercourse, and there is a possibility that bacterial colonies may be unique to each individual.
The research was the brainchild of Chapman, a senior lecturer in Forensic Science at Murdoch, who has spent more than a decade working with law enforcement at crime scenes and in the laboratory. Chapman and Dixon have coined the bacterial DNA makeup of the sex organs the "sexome."
Identifying the perpetrator of a sexual assault is complex and often requires the analysis of human DNA to catch the offender. But traces of DNA are not always found, such as when semen is not present, making the task all the more difficult for investigators.
"Current techniques for investigating sexual assault work well, however, if there aren't enough male cells then there may not be enough to link it to a person using conventional DNA analysis," Dixon said.
According to the scientists, their new research, published in Forensic Science International, shows they can detect that a heterosexual couple has had intercourse based on the bacteria found after the act.
"Some male bacteria stays on the female and some female bacteria stays on the male,” Dixon said. "The end goal is that we'll be able to take a swab, analyze the bacteria, and link it back to an individual, or at the very least eliminate suspects."
The researchers say even if the bacteria aren’t completely unique to an individual, it would likely be distinct enough to eliminate assault suspects.
“Although male bacteria may look relatively similar at a glance, we found the composition of each person's bacterial makeup is probably different enough to use for identification,” said Dixon.
Chapman said the findings could have a significant real-world impact on investigations.
"This research is a big step forward for forensic science and has the potential to lead to breakthroughs in cases that involve sexual assault," he said.
The plan is to further investigate uniqueness of individual bacterial fingerprints and the effect of elements like contraception and non-heterosexual couples.
"The fact is, we have now demonstrated that bacteria may be just as powerful as conventional forensic DNA, but with the added benefit of being available even when male human DNA is undetectable,” said Chapman.
The next stage of the research will further assess how the new technique can be implemented on a national scale.
Republished courtesy of Murdoch University.