The bacterium in our garbage that we change during sex

It turns out that fluids are not the only thing we are changing with our colleagues. New investigation this week shows that people also leave remains of the unique microbiome after the sex of the microbiome of their genitals, also known as their “sexome.”

Researchers at the University of Murdoch in Australia directed the study, which aimed to prove whether our microbiomas, the neighborhoods of bacteria living in or in our bodies, could be a viable marker for the investigation of forensic crime. Using genetic sequencing, they could reliably identify the traces of the genital bacteria of people transferred to their partner after Coitus. It is a fascinating finding, but the resulting technique could someday refine in a new tool to solve cases of sexual assault, researchers say.

We like it or not, our bodies are full of bacteria, even in our garbage below. Fortunately, these bacteria are (generally) harmless already vital for the normal functioning of the body. Many scientists have focused on studying how our microbiomas influence our health (particularly in the intestine), but Murduch researchers wanted to see if the unique composition of each person’s passenger bacteria could be used in a method for forensic identification, particularly the microbes called our genital home.

They have coined the neighborhoods of bacteria that live in our penises or vaginas such as the “sexome”.

“In forensic science we work on the concept that every contact leaves behind. With digital footprints that are obviously the waste of our skin and in the case of sexome, we are using the healthy bacterial communities that live in and within our bodies as a means to detect that transfer “, senior researcher Brendan Chapman, a forensic scientist in Murdoch, he told Gizmodo.

Scientists often examine the composition of microbiomas through the genetic sequence of a particular segment of ribosomal RNA called 16s. Historically, scientists have only been able to read (and unite) short lengths of 16 at the same time, allowing them to distinguish broad groups of bacteria from each other. But today, technology has progressed enough for scientists such as Chapman to identify these bacteria more clearly.

“Now we have more advanced systems for a massively parallel sequencing that can analyze longer chains of that genetic region 16s, which means we have a better vision of unique signatures within the community,” he explained. “It is a bit like the difference between just knowing the names of the chapters within a book, compared to being able to read the words on the page.”

Chapman and the last study of his team, published Wednesday in the newspaper shortageIt involved 12 monogamous, heterosexual couples. Couples were sequenced the baseline sexomas (using swabs collected from their genitals), they were asked to refrain from sex for different lengths of time (two to 14 days), and after they had sex again, they have sexual relations again, after which their sexomas were analyzed again.

“What we found was that there were unique DNA sequence variants of the woman we could identify in the man, and vice versa,” Chapman said.

Factors such as pubic hair or if man was circumcised did not seem to affect the ease with which sexomas between couples were transferred. The use of condom (practiced in three of the couples) affected these transfers, and most of the bacteria exchanged now come from women to men. But that still suggests that scientists can use this method to identify men who potentially committed sexual assault, even when the person used a condom.

It will take time and more research to know if our sexomas can really become the next forensic research border. The researchers point out that menstruation seemed to change the composition of a woman’s microbiome, for example, so scientists must understand and better assign these changes to explain that. Other important questions, such as how long it will take for people exchanged bacteria so as not to be traceable with tests, they still have no answer.

But Chapman and his team, including principal researcher Ruby Dixon, who is studying a doctorate based on this research, they hope for the potential of their work.

“They are the first days, and there is still a lot Forensic DNA that can help identify perpetrators of sexual assault, ”said Chapman.

And even beyond crime resolution applications, it is important to know more about our sexomas.

“In more general terms, the greater our understanding of the relationship we have with our bacterial passengers in our bodies, the better we can also use them to improve health results. We already know how important the intestinal microbiome for digestive health is, and the same is likely to be true for sexome, which provides protective characteristics for the vaginal microenvironment and perhaps even fertility, “Chapman added.