Why do people have different fingerprints? Our fingerprints are not that unique. footprints

Grooves on the fingertips are not only found in humans. But also, for example, in anthropoid apes. True, in primates, the fingers are decorated with parallel lines, so it is unlikely that it will be possible to identify an orangutan or gorilla by fingerprints - the patterns are almost the same. But the fingerprints of koalas are very similar to human ones. Even experienced experts sometimes cannot recognize at first glance whose print is in front of them: human or bearish.

Why are fingerprints needed? Initially, scientists assumed that the grooves on the skin help us hold objects more firmly in our hands, creating a good grip between the hand and the thing clamped in it, like the tread on car tires. However, this theory was subsequently rejected. A series of experiments showed that if the pads of our fingers were completely smooth, the grip would be stronger.

And then scientists created a new theory about the purpose of papillary patterns, which was fully confirmed. It turns out that the lines and curls on the fingers improve the sense of touch. When we run our finger over a surface, the patterns create special vibrations that help us to better feel the texture of the object. And the circles and curls created from the grooves lead to the fact that some of the lines on the fingers will always be parallel to the surface of the object when in contact with it. This structure of prints enhances tactile abilities.

Why are they different

Fingerprints are formed even before birth, at about 9-10 weeks of fetal development. The pattern on the fingers is determined by DNA, but it is not only influenced by genes. After all, identical twins have fingerprints that are similar, but still unique. Scientists believe that the position of the embryo, its blood pressure, the rate of development, and some other factors that simply cannot match in different people affect the formation of the pattern. That is why each of us has a unique pattern on the fingertips. However, is it really unique? After all, it is impossible to exclude the theoretical possibility of the presence of people with the same fingerprints. Mathematicians have calculated that the probability of such a coincidence exists, but it is negligible and amounts to about 1 chance in 64 million. This is successfully used by criminologists, because fingerprints help to identify the identity of criminals.

Erase identity

The idea of ​​the uniqueness of fingerprints was put forward by Englishman William Herschel in 1877. He served in the British administration in India (at that time India was a colony of Great Britain), and on duty he had to deal with contracts on which the Indians put a fingerprint instead of a signature. Then William noticed that the prints are always different from each other. And that served Herschel well. Indian soldiers often cheated: for a European eye, the faces of the Indians are very similar, and their names were often repeated, so the mercenaries came for a salary several times in a row, claiming that they did not receive money. After Herschel forced the soldiers to put their fingerprints on the payroll, the deception was put to rest.

And already at the beginning of the twentieth century, the British police began to conduct fingerprinting to identify criminals. Since then, criminal personalities have fallen on hard times, because fingerprints could give them away at any moment. Therefore, the criminals, who lit up their fingers in the police files, did their best to get rid of the patterns on the fingertips.

There are cases when the skin on the fingers was simply cut off. However, it turned out that after the wounds had healed, exactly the same prints appeared on the fingers as before.

Known in the 1930s American gangster John Dillinger, in order to hide from the guards of the law, he underwent plastic surgery and tried to etch his fingerprints with acid. But when the police shot Dillinger, his identity was finally established precisely from the prints - the acid did not dissolve the unique patterns.

Another American robber came up with an even more exotic way to deceive the police - he performed a skin graft operation. He himself acted as a donor - the skin was taken from the criminal's chest and transplanted onto the fingertips. However, even this did not help - a few months later the skin on the fingers was renewed and the treacherous lines appeared again! And there is no way to deceive the dactyloscopic examination to this day.

The existence of twins is an amazing phenomenon, which is not so rare these days. If you look at the situation from the outside, then their appearance in this world can be compared with the plot of a good science fiction novel. The twins themselves, as a rule, do not immediately manage to get used to the idea of ​​​​the presence of an identical double nearby. In this article, we will tell you little-known and amazing facts about twins.

Identical twins have different fingerprints

The term "identical twins" should be taken literally. They are called so because they are practically indistinguishable from each other. But even the most similar twins will have different fingerprints. This feature is strictly individual.

According to experts, their shape depends on the position of the fetus and the density of the amniotic fluid, which spirally wraps around the fingers at different times. Identical twins occupy different parts in the womb, so their hands are pressed to different places.

Fingerprint testing is the only reliable way to tell one twin from the other.

Sometimes one twin disappears

One of the creepiest things that can happen when a woman is pregnant with twins is Vanishing Twin Syndrome.

First, the mother finds out on an ultrasound that she has twins. A few months later it turns out that one of them died right in the womb.

According to statistics, this happens in 20-30% of cases of multiple pregnancies.

Twins separated at birth often lead odd lives

Sometimes twins are separated at birth. At the same time, they do not even suspect that an almost complete copy of them exists somewhere. Surprisingly, at the same time they begin to lead parallel lives in adulthood.

One example is Paula Bernstein and Elise Shane, who reunited at the age of 30. They were surprised to find that both became writers, had the same political views and passions in art. In adolescence, they suffered from identical intestinal disorders, in addition, they edited school newspapers, and studied cinema in college.

Twins begin to communicate even before birth

The womb is very similar to your first apartment outside of school. It's cramped, dirty, and you spend way too much time sucking weird drinks out of an even weirder pipe.

But this first apartment is completely yours, and it's brand new to you, so you dig it. The only thing that can make it even better is a cool, friendly roommate, which is exactly what the twins have.

Twins have an unusually strong bond with each other. According to recent research, they begin to communicate and feel sympathy for each other even in the womb.

For example, it was possible to establish that already at the 14th week of pregnancy, the twins begin to extend their hand to their brother. By the 18th week, they are already regularly touching their partner. At the same time, they are careful when touching the twin's eyes so as not to injure.

"Mirror Twins"

"Mirror twins" have quite a lot of differences compared to the more common identical twins.

In fact, they look exactly the same, but their functions are mirrored. They all have the same genes, but one twin can be left-handed and the other right-handed.

If one has a noticeable birthmark on the left leg, then the "mirror twin" will have a birthmark in the same place, but on the right leg. Often they have bite on opposite sides. Moreover, despite this strange asymmetry, most often, they are monozygotic.

The mind of Siamese twins can be connected

Tatiana and Krista Hogan are twins whose skulls are fused together. The fact that they are alive is already a miracle. Most of these phenomena require surgical separation in order to survive.

Even more incredible is that there is a physical connection between their brains, which neurosurgeons call the thalamic bridge. Thanks to this, they can even feel each other on a sensual level. For example, if Krista tries some new food, Tatiana tastes it.

Twins can have different fathers

It's hard to say where this strange fact would be more appropriate: in a science fiction novel or a sitcom. It is now reliably known that twins can have different fathers.

The fact is that twins appear when a woman produces two eggs, each of which is fertilized by a separate sperm. Therefore, if she meets in the same period with two men, this is quite likely.

Such situations most often occur in animals, but they also occur among people. There are at least a few proven cases.

Gemini communicate in their own language

This phenomenon is observed in 40% of twins. It's called cryptophasia. When twins are still very young, just beginning to learn speech, then, unlike most children, together with their partner they are able to create a language that no one else will understand.

These autonomous languages ​​tend to disappear when toddlers learn adult language. But this doesn't always happen.

Matthew and Michael Youlden are two adult twins who have not lost the language they spoke as children. From about the age of 7, they began to actively develop it. They had their own alphabet, grammatical rules, it became possible to fully communicate on it.

They call their personal language Umeri. This is an amazing phenomenon. Interestingly, the twins keep it a secret from the rest of the world.

The twin gene is passed down from mothers

Counts. that a woman's ability to produce two eggs instead of one. transmitted genetically. So if you didn’t have twins in your family line for several generations, it’s unlikely that you will have them either.

The birth of twins is always directly related to ovulation. Years of research have concluded that the genetic predisposition is transmitted only from woman to woman.

There are more and more twins

In 2014, it was found that a record number of twins were born in the world. Since 1980, the frequency with which they were born has increased by 76%.

Basically, this is due to the fact that modern women give birth all at a later age.

The fact that the patterns on the fingers are unique, people assumed thousands of years ago, but this issue aroused real public interest in 1877, when the Englishman William Herschel suggested that the papillary pattern of our fingers remains unchanged throughout a person’s life. Many researchers, and especially criminologists, asked themselves the question: "Isn't a fingerprint a unique identifier for each person?" This would open up completely new possibilities in the criminal investigation and would make it possible to keep an unmistakable record of persons suspected of committing a crime. But before this idea could become a reality, it was necessary to develop a classification system for papillary patterns and, most importantly, to prove that the papillary pattern of each person is unique. And if the experts coped with the first task rather quickly, then the proof of the uniqueness of fingerprints still raises questions from many experts.

Human palms are made up of two layers of skin: the cutis, the bottom layer, and the epidermis, the top layer. These layers do not adhere tightly to each other, so over time, folds appear on the cutis, from which our unique papillary patterns are formed. This happens around the seventh month of the fetus's life, so a person is born already with unique fingerprints. As the child grows older, the print increases, but the pattern remains the same. How did the researchers prove that each fingerprint is unique? Actually… not at all. Simply because it's impossible. This assumption was made on the basis of the examinations and analysis of fingerprint databases, among which it was not possible to find matching ones. However, it is not yet possible to take fingerprints from all 7 billion people inhabiting the planet and analyze their fingerprints. And if all the people who have lived on the planet throughout history, then the task becomes completely impossible.

Fingerprinting recognizes that it is still possible to re-draw on the fingertips. It all depends on the probability of this event. Most likely, a complete match of papillary patterns can happen no more than in one case in 64 billion. And if we take into account that, according to rough estimates, about 107 billion people were born on Earth in the entire history of its existence, then, for sure, two people, even if they lived in different eras, had the same fingerprints.

Interesting Fingerprint Facts:

- The Argentinean police were the first to use the Galton method in determining fingerprints.

– Juan Vucetih, a member of the Argentine police, was the first police officer to catch a criminal using fingerprinting. It turned out to be a woman who killed her own sons. After their deaths, she cut her throat to avoid being found guilty. However, after killing the boys, she left fingerprints on the door, so she could not escape punishment.

“Of all the types of forensic examinations, fingerprints are the most evidentiary evidence found at a crime scene.

- The pattern on the soles and toes is also individual for each person. Often it helps to find a person as well as the drawing of fingers.

- It is fingerprints that can show that a person has used drugs - the skin secretes fat, which includes the remains of any substances in the body.

- Your cat will not be able to escape responsibility either - after all, the imprint of his nose is also individual.

Illustration: depositphotos | JohanSwanepoel

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Incredible Facts

The idea that we all have unique fingerprints that can be identified from computer data is wrong, the expert argues.

Fingerprints for identifying criminals played a big role in finding guilty.

However, the British expert of the Ministry of Internal Affairs Mike Silverman(Mike Silverman), argues that human error, incomplete prints, and false positives result in fingerprints as evidence are not so reliable, as previously thought.

Fingerprints

No one has yet proven that fingerprints are unique, and family members may have the same elements of papillary patterns.

There are other problems, such as when scanning the fingerprints of older people, whose skin loses elasticity, and in rare cases, their fingerprints become smooth and inexpressive.

"Basically, you can't prove that no two fingerprints are the same. It's impossible, like winning the lottery, although people win every week," explained Mr. Silverman. "We need a specialist to determine that the print taken from the crime scene and from the person in question belongs to one finger."

There are numerous cases where fingerprints have mistakenly pointed to innocent people.

Besides, Many things affect the accuracy of a print. such as smear and dirt.

Unlike in forensic sciences, since DNA is an analysis that gives a statistical probability of a match, experts in fingerprinting usually state that the evidence is either a 100% match or a 100% exception.

Previous research has shown that experts don't always draw the same conclusions about whether a print matches the one at the crime scene when they're presented with the same evidence twice.

Fingerprinting

Fingerprinting is the field of study of fingerprints. The name comes from the Greek words "daktylos" - "finger" and "skopein" - meaning "to study".

There are furrows on our fingers that help us grasp objects. They provide us with both grip and friction, preventing objects from easily falling out of our hands. They also improve the sense of touch.

· When we touch objects, we leave fingerprints thanks to the natural oils contained in the skin and the salts secreted by the sweat glands.

English anthropologist Francis Galton (Francis Galton) classified fingerprints into such types as "spiral", "arc" and "loop".

· Koala fingerprints are similar to human fingerprints. The difference is that koalas have two thumbs and claws.

Fingerprints are formed before birth at 3 months of fetal development.

· Exist 1 in 64 billion chances that your fingerprint matches that of another person.

The fingerprint scanner

Apple has developed a Touch ID fingerprint scanner that can be used as a password.