Why are human fingerprints different?

Tram Ho

118 years ago, brothers Alfred and Albert were sentenced to death for theft. The cause of the incident was that two people had murdered a couple in a shop in the suburbs of London. The crime scene left only two people’s fingerprints. Investigators made convictions based on these fingerprints.

Sentencing based on fingerprints is a very common thing nowadays, but it was shocking at the time, because it was the first murder case to be tried by fingerprint evidence. . The pioneer in using fingerprints as evidence was fingerprint expert Galton, who spent decades collecting different fingerprint samples and conducting in-depth research on them.

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Galton classified fingerprints, studied the characteristic structure of fingerprints and finally confirmed that fingerprints are reliable evidence for identity verification, which can be used to identify criminals. .

Now we all know that everyone’s fingerprints are different, and fingerprints are even more unique than DNA. For example, identical twins will have the same DNA, similar appearance and height, but their fingerprints will be completely different.

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Fingerprints are made up of ridge-like protrusions known as friction ridges, and in the middle of the fingerprint are dense pores that connect to sweat glands under the skin. By comparison, it can be said that sweat is equivalent to ink, and fingerprints are equivalent to seals, that’s why people can leave fingerprints on things.

We can determine a person’s identity by observing the number of fingerprints, the arrangement of shapes and sizes. There are no two snowflakes in the world that are exactly the same and no one has the same fingerprints. Scientists once calculated that the probability that two people have the same fingerprint is about 1 in 64.5 billion.

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Everyone has their own unique fingerprint, but most of the living things on our planet do not have fingerprints. For example, there are no obvious fingerprints on the toe pads of dogs and cats. But a few other mammals have fingerprints, including primates, our closest relatives.

Some scientists believe that fingerprints play a very important role for human touch, it can not only make touch more sensitive but also increase friction between fingers and objects. improve human grip.

The same is true of other animals, such as tree-climbing rodents, which typically also have prominent ridges on their toe pads, and burrowing rodents that also have such ridges on their toe pads. toe pads.

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Normally, when a human fetus develops to 150 days, it has developed a fingerprint, and this fetal fingerprint will not change.

Unfortunately, until now, science has not found out the formation principle of fingerprints, so they can only analyze the formation mechanism of fingerprints through speculation.

First of all, the formation of fingerprints is random. Eye color and hair color are determined by genes themselves, but fingerprints do not have this feature, no one can guess a child’s fingerprint before birth is bow, circle or spiral. Therefore, the formation of fingerprints is the result of many accidental factors such as genes and environmental factors.

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In addition, genetic diseases can also affect fingerprints, for example, a person with a loss of chromosome 5 will have severe intellectual disability, a much smaller head than a normal person, thick ears. and fat, and their fingerprints also had more pimples-like marks than usual.

Environmental factors can also affect fingerprints, for example, during pregnancy, if you are malnourished or infected with certain viruses, your baby’s fingerprints may appear many buckets. .

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In fact, from a few centuries ago, almost all countries in the world began to use fingerprint “recognition technology”, although the technology at that time was not as complex as it is now, the frequency usage is quite high.

The ancient Babylonians often used fingerprints on clay tablets to record business transactions, Asian countries also pressed fingerprints on paper with ink to mark only their identities, illiterate people in ancient India it was also possible to use fingerprints instead of signatures.

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Scientists have now developed many biometric technologies that, in addition to fingerprints, include dental characteristics, iris scanning and DNA recognition, which can determine the identity of a person. person. However, fingerprint recognition is still the most accurate and most commonly used method of identification.

Today, anyone entering the United States must leave their fingerprints at the port of entry, and it only takes a few seconds to leave identification.

The fingerprint recognition and collection system in the United States is one of the most advanced currently available, within half an hour it can find any fingerprint record and associated information. related to the owner of that fingerprint in the fingerprint database of nearly 50 million people.

Source: Grunge; phys.org; USGS

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Source : Genk