The Bacterial signatures Individuals of genital areas could serve to identify the authors of sexual aggressions in cases where there are no other biological remains, such as sperm, according to a study published on Wednesday In the magazine iscience. From a series of experiments with 12 stable couples, researchers show that bacterial species are transferred between both individuals during sexual intercourse and constitute a unique footprint that authors have called “sexome”.
“This research is based on the forensic concept that every contact leaves a trace,” says the principal investigator Brendan Chapmanfrom Murdoch University, in Australia. “Until now, few studies have explored vaginal and penis microbiomes in a forensic context,” he adds. “This research shows that we can observe microbial traces in the genital microbiomes of heterosexual couples after sex.”
A study with 12 couples
For the work, the researchers recruited 12 monogamous heterosexual couples to investigate whether these sexomas are transferred during sexual intercourse, even when a condom is used. At the beginning of the study, each participant collected samples of their genital microbioma through swabs and identified microbial firms for each participant through RNA sequencing.
This research shows that we can observe microbial traces in the genital microbiomes of heterosexual couples after sex
Brendan Chapman
– Murdoch University researcher, in Australia, and co -author of the study
After a period without contact, the authors asked couples to have sex and collected samples again from the genital microbiome of each individual. What they saw was that the unique bacterial firm of a participant can identify in the sample of their sexual partner after the sexual relationship.
The researchers also analyzed how different circumstances influenced, as if the men were circumcised or the presence of pubic hair, but none of these factors seemed to affect the transfer of bacterial species. Three of the couples reported having used a condom and the analysis showed that it did not completely inhibit the transfer of microbial content and that most of the woman occurred from the woman.
A “promising tool”
“This is a promising tool to test an aggressor after an aggression and means that there may be microbial markers that detect sexual contact even when it was used,” says Ruby Dixon, co -author of the work and researcher at Murdoch University.
This is a promising tool to test an aggressor after an aggression
Ruby Dixon
– Labor co -author and researcher at Murdoch University
Although it is a proof of concept, researchers believe that the system can be useful in cases of sexual aggression where the DNA analysis of biological remains is ineffective. “The application of Sexoma In cases of sexual assault are still in its beginnings, ”says Dixon. “It is important to completely understand the external factors that can have an impact on microbial diversity of both men and women, and this is something we plan to continue studying.”
Methodological doubts and possible errors
“The methodological contribution is that they use a robust sequencing with Pacbio, which allows very long DNA readings, and that is why they know very well where the bacteria comes from,” he says Country roseresearcher of the human microbiota group at the Ramón y Cajal hospital (SEIMC-GEMBIOTA) in statements to the SMC. “The limiting factor of this technique is that, if there is a wash of the genital area after sex, it will be very difficult to find the bacteria of the couple.” In any case, this technique warns in no case will replace the detection of the chromosome and in the case of men, although it may be useful in specific cases.
The limiting factor of this technique is that, if there is a washing in the genital area after sex, it will be very difficult to find the bacteria of the couple
Country rose
– Researcher of the human microbiota group at the Ramón y Cajal hospital (SEIMC-GEMBIOTA)
“The important limitation it has is the methodological technique, because instead of sequencing genomes of bacteria, they sequence only one gene,” he says Mireia Vallès-ColomerChief of the Microbioma Research Group of the Pompeu Fabra University (UPF) to eldiario.es. “They admit that it is a proof of concept, but it could give false positives. And, of course, in those conditions it is very dangerous. ” In his opinion, the technique will gain resolution when the genome can be sequenced or use better technologies, and that is why it has been published in a scientific journal of little impact.
They admit that it is a proof of concept, but could give false positives. And, of course, in these conditions it is very dangerous
Mireia Vallès-Colomer
– Chief of the Microbioma Research Group of the Pompeu Fabra University (UPF)
“The study should have done a more careful analysis of variability in sampling, since, although 10 aftershocks were taken, only one case was sequenced, which does not allow to establish which basic variability we could expect in sampling.” , he comments Toni GabaldónICREA Research Professor and Head of the Comparative Genomics Group of the Biomedical Research Institute (IRB Barcelona) to SMC. “I think that the data allow to glimpse future possibilities, but do not provide evidence that it can, for example, identify the aggressor from the possible variants detected in a victim. It is foreseeable that, unlike this study, there are no shows taken shortly before the aggression. ”
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