Interesting question, right! Do you know not only in every individual but fingerprints differ in your fingers too? Yeah, you read that correctly. Let me give you a practical example. We all use smartphones, where we put our fingerprints as one of the security features so that no one else can unlock them.
Now here comes the exciting part, you might also have noticed if you have recorded the thumbprint of your left hand in your security features, it will only consider that. Even if you put your right hand’s thumb, it won’t consider that until and unless you have recorded it.
Check it out if you haven’t, and if it opens, then congratulations, you are that one person among 64 billion chances. Even twins differ in fingerprints which is one of the reasons why we use it in biometrics though that topic is for another day.
Here we already know that it’s different, but why?
We have different types of patterns in fingerprints, which differ in ridges and minutiae, and genetically influenced volar pads. Their patterns vary in every individual, which is why we have different fingerprints.
Scientists have been studying these fingerprints since the 19th century. As early as 1892, English scientist Sir Francis Galton wrote a book about using fingerprints to solve crimes. However, it was not until 1896 that Sir Edward Richard Henry developed a way to classify fingerprints based upon their general ridge patterns.
However, it is essential to know what “uniqueness” means in this context. When people claim that fingerprints are unique to the individual, they do not mean that there are no two people with the same types or configuration of arches, loops, and whorls on their fingers, because there are people who have the same number.
Each of these classes can be further divided into numerous sub-categories. Fingerprints can also show slight racial variation. People of African ancestry tend to have a multitude of arches, whereas people of European background have many loops, and those of Asian descent have a relatively high frequency of whorls.
Factors Responsible For Individualization Of Fingerprints
As described by biologists, they differ because of genes and developmental conditions inside the womb of a mother.
- Genes represent your parents, who play a role in forming your fingerprints. If your parents’ fingerprints have a specific pattern, you might be likely to develop it too. Genes are like instructions written inside the baby’s body. The patterns start to form when the fetus is barely three inches long. The process begins in about 10th week of the conception, and by the end of 14th-week, fingerprints get formed, but there’s no precise process that creates it. The genetic code mainly decides the factors in the formation of fingerprints. They do not determine the patterns that are going to form.
- It forms biologically, which means the fetus’s development also plays a role. When the upper (epidermal) layer, basal layer of the epidermis, and the inner (dermis) layer crumple due to pressure (tension and compression) in the fetus, it forms patterns. However, these layers do not grow at the same pace in everyone. If one of the layers of cells grows faster, it stretches and pulls the others. Numerous environmental factors are assumed to influence the formation of fingerprints, including blood pressure, oxygen levels, nutrition of the mother, hormone levels, the exact position of the fetus at particular times, and density of the amniotic fluid. These many factors decide how each ridge is shaped. As the fetus moves, fingers can rub against the side of the womb. These factors of tiny forces push the skin as it grows. Combinedly, they mold the direction of the growing ridges, which results in a unique fingerprint unlike anyone else’s. Patterns are formed from inside the skin, that’s why they cannot be changed.
How The Ridges Are Formed?
- Throughout the development of fingers, volar pads are formed on the surface of palm and soles of the feet of fetus at around 7-8 weeks of pregnancy. These are thick pads of skin developed by a kind of swelled stem cell tissue called mesenchyme under the other layers of skin.
- The volar pads remain swelled and rounded until or after the 9th or 10th week of the gestation period when they start to change their size and position. Eventually, they begin to disappear, and fingerprints are formed simultaneously. The position and state of the volar pads decide what kind of patterns will be included on the fingers– arches, loops, or whorls.
- If the subsiding volar pads are slanted to one side when the first fingerprint ridges are formed, the pattern will also be slanted, forming a loop.
- If the volar pads are still prominent but flat, whorls will be formed, and if the volar pads have almost disappeared, patterned arch ridges will be developed.
What Are Friction Ridges And Their Applications?
- If we discuss it logically, then what we have on our fingertips are not fingerprints—they’re friction ridges. Plenty of sweat glands is open by pores along these ridges. These are the oily marks left by the ridges on surfaces one-touch or the prints made by putting ink on the fingertips as in booking persons upon arrest. The oil of a fingerprint appears not only from the sweat but from other surfaces one has touched, such as the facial skin and hair. Freshly washed hands leave less visible or noticeable fingerprints.
- Friction ridges offer two purposes. One is an anti-slip function. When touching or grasping a wet object, these ridges act like the tread on a car tire to channel water away from the contact points, providing a better grip, while the second function is tactile sensitivity. In the dermis layer of the skin just underneath these ridges, we have vibration receptors called lamellar (Pacinian) corpuscles.
- Ridges at our fingertips are helpful for reading information. For example, a blind person uses his fingertips to read the Braille language. A doctor can read the disturbances in the patient’s body using touch (palpation).
Imagine if you don’t have them after getting to know so much about fingerprints. There is a small minority of people who are born with smooth fingers or voided prints! This condition is called Adermatoglyphia, a rare genetic disorder in the chromosomes. That causes a person to have no fingerprints.
There are only four families in the world that do not have fingerprints. Those people often experience unpleasant side effects, including skin blistering. That’s because the pattern ridge structure at the surface of your fingers does not allow fluid to accumulate thus reducing the risk of blisters. In Canada, currently in Manitoba, there is one family with adermatoglyphia. All of them are females.
If you do not have fingerprints, you will face difficulties obtaining a passport or traveling outside the borders of your country.