The Secrets in Your Fingerprints

You aren’t special,

But you are unique.

Did you ever consider there to be a difference? You really aren’t that special. You’re a dime a dozen. A person in the crowd. Trying to fit in. Everyone’s special – I don’t have time to stroke your ego.

But you are unique.

Just look at your fingers. Imprinted on them are patterns that are unique to you. Leave your fingerprints on the bathroom door and the FBI can determine your gender. And within a few years, your age and ethnicity as well (they do this by looking at the sweat content left behind, not the patterns).

Look at your fingers again. Look at the patterns. You might see one, two, or all three major types of patterns: Whorls, Loops and Arches. There’s a large chance that they’re like your parents. That’s because these patterns are genetically inherited.

Play the video to see the Different Types of Fingerprint Patterns; from SciShow at 1:58

But if you look closely, you’ll realise that every print is unique. And by extension:

You are unique.

But what makes my fingerprints unique, if they are inherited?

Even though the pattern is similar, the randomness of
(1) the arrangement and
(2) the spacing of each line, are different.

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Maybe you’ll go on a thought experiment with me.

Imagine when you’re still in your mommy’s tummy. Your fingers are tiny but growing. Consider the tips of your fingers as fertile farm land.

Swelling of the Fingertips. From Wertheim and Maceo (2002), p61

Farmers decide to scatter maple seeds around this area. As you grow, the tips of your fingers begin to swell, like a hill. A smooth and rounded hill grows out at each fingertip. Then, the maple trees begin to grow randomly.

Trees that are close by join to form a line. These lines make a pattern. This pattern turns out to be the prints on your fingers. The swelling at the fingertips shrinks until it is flat. This also adds to the random spacing and arrangement of your prints.

Growth of Finger Patterns. From Wertheim and Maceo (2002), p49

Your genetics control the shape of the swelling
If the hill is high, we will develop a whorl pattern. If the hill is a low and flat, we will develop an arch pattern. If the size of the hill is somewhere in between, we will develop a loop pattern.

Randomness from the environment dictate the formation of the patterns
The hills can grow to be slanted and asymmetrical. Some trees may grow, but others may not. Just like how trees depend on temperature and humidity to flourish, the density and pressure of the fluid in your mommy’s tummy affect how your fingerprints develop.

That’s why even identical twins don’t have the same prints. Mommy’s tummy is a big place and the conditions are not the same everywhere.

And these are the prints that you end up with for the rest of your life – unless you purposely scar them.

How your fingerprints grow through time. From Wertheim and Maceo (2002), p67

Ah, perhaps I’m wrong. Maybe the fact that you are the product of so many minor things, does make you special, eh? Why not. Embrace your damned special-ness and, um, make a difference in the world? Bah, till next time.

Shout out to Nathaniel from IH for suggesting this post. Got suggestions for other topics? Leave them in the comments below!

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If you want to see the ridges of your fingerprints, check out the Science Gallery: Blood Exhibition at the University of Melbourne.  They have a cool microscope thingy on 2nd floor to let you see your fingerprints up close. You can even see your sweat pores!

2 August – 23 September; Science Gallery Melbourne, 781 Swanston Street, Parkville, near ERC (Eastern Resource Centre)

***

Want to know more?
Wertheim, K. and Maceo, A. (2002). The Critical Stage of Friction Ridge and Pattern Formation. Journal of Forensic Identification, 52(1), pp.35-85.

Forensic Evidence from Fingerprints

Watch’s SciShow’s Fingerprint Video


7 Responses to “The Secrets in Your Fingerprints”

  1. Murraya Lane says:

    I found this post really interesting! I’ve never really thought about the uniqueness of fingreprints before but I really enjoyed reading about it, especially in terms of fertile farm land! I thought that was a really cool analogy! good job!

  2. Jun-Ting Yeung says:

    Thanks, glad the analogy worked.

    You should go to the Blood Exhibition beside the Eastern Resource Centre (ERC). They have a close-up fingerprint scanner which can let you see the ridges/grooves and the sweat cells on your fingertips. It’s so cool.

    https://melbourne.sciencegallery.com/blood/melbourne/

  3. Jun-Ting Yeung says:

    Thanks! Glad it helped

  4. Eugene says:

    Very insightful post JT – interesting read!

  5. Jun-Ting Yeung says:

    Glad that the analogy worked. Not sure how it would have been received. It was long shot!

  6. Nicholas Fawcett says:

    This is a really interesting and unique topic (much like our fingerprints)!
    While I knew our fingerprints were unique, I never thought about how they were formed. I loved the use of the metaphorical land-based analysis, very clever. Your use of inclusive language and colloquialisms is great, it makes the reader think in the context of their own experience.

  7. Andy Low Jian Yang says:

    Love the post! Really makes you think twice about how you are able to stand out as a true individual in the world population by more than 7 billion others. Good use of the analogy of the farmers and their fertile to land to succinctly describe your uniqueness.