Identify criminals through ... bacteria

We already have biometric technologies to distinguish individuals from replacing passwords such as fingerprints, voices, retinas, DNA . Recently, scientists have devised another bold way. for that - bacteria.

Crime can be identified by bacteria

My hands, bacteria . my

When you touch something, you leave a fingerprint - the twisted veins created by the sebaceous gland below the skin help identify who you are. You can also leave traces of your DNA, which also helps identify you. And not only that, you also "mark the territory" with microorganisms on people. It is important that the bacteria are constantly born and "scattered" around you. As long as you touch something, they immediately jump to the other side of the surface.

Our hands are not only fingerprints, they also have . bacteria

Through many years of research, scientists have realized that most people have a separate "bacterial" system unlike others . Although we share strains of bacteria through intimate gestures, the exact list of each species varies from person to person. Curtis Huttenhower, of the Department of Public Health at Harvard University, said: " If we choose a group of people, the microorganisms on each person will be different but their genetic information is similar."

Based on this, quite a few studies have been conducted. They are mostly exploited in the field of criminal science , where sometimes the " devil " perpetrator knows how to remove his fingerprints and DNA fragments too little to expose them.

What does this discovery mean in crime fighting?

In 2010, a team at the University of Colorado discovered the bacteria found on keyboards and computer mice (the ability of smartphones is equally high) coincides with those on the owner's skin, rather than from other people. Or just last year, Simon Lax and Jack Gilbert from the University of Chicago could distinguish 18 experimental volunteers, based on the bacteria samples in their homes.

There are millions of phones the same but only a few are yours or ever yours!

Or most recently, Lax and a student swapped each other's habitats for two days, they exchanged phones for each other, shoes for each other . Then they recognized beyond the new bacteria samples, the items above. still keep track of the old owner. This shows that bacteria can also be used as a way to know who is the former owner of the item . Suppose an item is robbed and many people come to receive it, or the criminal uses the victim's item like his own. In addition, depending on the environment of the item, the ability to transmit bacteria is also different. For example, soles are easy to pick up bacteria from the floor they step on. This feature can be used to re-guess the direction of the perpetrator / victim's movement when the incident occurs.

However, there are important questions as to whether the bacterial method is accurate on a large scale, where there are many people passing by? Does it indicate exactly who to look for without causing confusion? Are the results consistent? While fingerprints and DNA are always fixed, the microflora is constantly changing - so will the bacteria "scatter" a few weeks or months ago still show their true owner?

Where we go, bacteria stay

To answer these questions, Huttenhower's team began to study data from the Human Microbiome Project. This project collects bacteria in the intestines, skin as well as other parts of the body of 120 people. The team used an algorithm to synthesize volunteer data from their first sampling. This algorithm will extract parameters such as bacterial strains, the lines between them, the gene . and bundle it together into a "code" that is only true for each person. Later, the group invited volunteers to return to sampling after a few months to see if the "code" still identified them properly.

But the sad result is that only one-third of the first "codes" recognize their owners. With this ratio, the above algorithm cannot be used as a criminal method to identify criminals. However, the results appear to be more accurate when the group focuses on the intestinal flora . They proved quite stable in time, with an accurate rate of up to 86%!

Still need more improvement

"It is only the first step," Huttenhower said. "Accuracy can only increase if we have more sequential data and better decoding algorithms . " But he went in a rather strange direction - wrong number. "Because the microbiological system changes over time, we want to find as many errors as possible, so we revised the algorithm towards finding the wrong values ." That way, the decoding program may not identify each person based on their bacterial pattern, but it will almost never identify anyone. For example, a group of suspects has 10 people, Huttenhower's program may not recognize exactly who the culprit is, but it can limit the number of suspects to 2-3 people.

The results of Huttenhower's research also open up other understandings about human microbiology. Our bodies, which are particularly intestinal, are "occupied " by some specific strains of bacteria and they are very stable. The density of each species can fluctuate depending on activity, but the number of species in them is almost constant for decades. But the reason why scientists are still trying to decode.

Know better than yourself

It's possible that our immune system has decided "whoever lives ". Or maybe their existence is due to the "superhuman", when a proactive strain "occupies before the field", they will decide which " immigrants " will "stay". . What you should know is that in addition to fighting our immune system, there is also a battle between "species of living" together. This is almost similar to the mafia gangs in human society, where police sometimes "relate " to this gang to purge other gangs. Of course, the " common" benefit here is an orderly society, or a healthy body.

The human body is the "home" of hundreds of bacteria

And, of course, the above is only true when our bodies are healthy. If you are accidentally infected with a dangerous "super crime" such as tuberculosis, influenza, tetanus, plague . they will disrupt the inherent balance and many "resident " bacteria in your body. You can be destroyed.

Take the gastrointestinal or diarrhea disorder, for example, from changing the microbial balance in the intestine, especially the bacteria needed for digestion.

Will bacteria form the "personality" of each person?

Huttenhower commented: " We are not just microbial robots, but we are personally an independent robot for different strains of bacteria, which have been around us for decades." And although the accuracy from "measuring" bacteria may not be high, it is still valuable in criminal science. "If you" drop "the bacteria around, it is highly likely that he will" drop "both his DNA and identify it with the already developed DNA".

In other words, in case the information from the DNA is not enough, the information from the fingerprint or bacteria can still help the police determine who caused the crime by combining the data together.