The mystery behind our unique fingerprints explained

A fingerprint is the most compelling evidence in a forensic laboratory when it comes to identifying a person. But why are individuals’ fingerprints different from one another?

How a fingerprint is formed

The uniqueness of every individual’s fingerprint forms during the development of the foetus.

The environment of the womb is what decides the outcome of a fingerprint. While still a foetus in your mother’s womb, your fingers and toes are developed within the first six months.

At this point, the faint lines on the fingers and toes are already there. In the last three months before childbirth, these lines deepen and thus, the forming of your fingerprint is completed.

Surprisingly, even while scientists can pinpoint the time when fingerprints are created, they still do not have a clear understanding of the process involved in creating them.

Most scientists agree with the theory that the middle layer of skin (basal layer) is scrunched between the inner layer (the dermis) and the outer layer (the epidermis).

It has been suggested that the basal layer grows much faster than the other layers of skin.

This inconsistency in growth makes the skin bundle up, forming the folds in the epidermis and dermis. The folds show from the outside as patterns of ridges on the fingers.

Because these patterns are formed at the foetal stage, they are unchangeable and cannot be destroyed from the outside. No matter what skin injuries one suffers, the inner structure of the fingerprint will not change.

So what about the patterns we see on the skin of our fingers? Well, these ridges can be changed.

If you often perform the same activities, such as bricklaying or nail biting, the part of the skin in most frequent contact to the outside can wear down and become unidentifiable.

Because of this weakness of the outer skin, many criminals burn off their fingerprints so as not to leave behind any marks.

However, in most cases, because the root of the fingerprint is in the deeper layer of skin, if you leave an injured finger to heal over time, the ridges will grow back just fine.

Why are our fingerprints unique?

The patterns of the fingerprint are decided by two components: genetics and environmental factors. Some of those environmental factors are:

• Blood pressure

• Blood oxygen levels

• Nutrients from the mom

• Fluid hormone levels

• Position of the foetus

• Position of the foetus’ hands

• Pressure of the amniotic fluid

With so many variables that decide an individual’s fingerprint patterns, it is extremely rare for two people to have a matching set.

That’s why your fingerprint will always be one of your most unique features.

This article first appeared in hellodoktor.com and was reviewed by Dr Duyen Le. The Hello Health Group does not provide medical advice, diagnosis or treatment.