Rosa del Campo
Researcher at the Ramón y Cajal Hospital and member of the Specialised Group for the Study of the Human Microbiota of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC-GEMBIOTA)
This article studies the possible usefulness of the sexual microbiota ('sexome') to identify aggressors in cases of [sexual] abuse. Until now, the reference method is to find the Y chromosome – provided that the aggressor is a man, which is most commonly the case. In the case of using a condom, there is not much human DNA, and that is why the 'sexome' would be useful.
The researchers recruited 12 stable and monogamous couples, who go 14 days without [sexual intercourse] and take samples themselves from the penis and vagina. The methodological contribution is that the researchers use robust sequencing with PacBio, which enables very long DNA readings, and therefore they know very well where the bacteria come from. They also study the influence of external factors such as the use of a condom, lubricants, etc.
Men have a microbiota on the penis (very similar to that of the skin in other areas) that is much more diverse than the vagina's microbiota of women in the vagina. The limiting factor of this technique is that if the genital area is washed after sex, it will be very difficult to find the partner's bacteria. They have also studied couples who regularly have sex, and that can influence the results. In no case will this technique replace the detection of the Y chromosome in the case of men, but it can be useful.
I don't like the word 'sexome', it should rather be called 'genital microbiota'.