Do identical twins have identical fingerprints?
No, identical twins don't have identical fingerprints. While they can share almost 100 percent of their DNA, their fingerprints form after a single zygote splits, so their fingerprints are distinguishable and every person has prints that are unique to them.
The not-so-perfect crime
When we told people we were pregnant with identical twins, the amount of people asking us if our twins would be able to commit a crime and frame their twin was shocking.
For those of you whose curiosity has now been piqued, the short answer is no.
For the long answer, read on.
Identical twins are not 100 percent identical
"Identical twins" does not mean "identical DNA."
While identical twins can look and act very much alike, it's important to recognize that they are not carbon copies of each other. Even though you might not be able to tell them apart just by looking at them, each twin is genetically unique.
Yes, identical twins do share a large portion of their DNA—but not 100 percent. They're not genetically indistinguishable.
In fact, the earlier a set of twins splits, the more time each zygote has to form their DNA independently. But fingerprints aren't set solely by genetics (more on this below).
While most identical twins share almost identical DNA, compared to their counterpart, about 15 percent of identical twins have genetic variations, which can lead to some genes or traits being suppressed.
When these gene and / or trait suppressions happen, they can cause one twin to look slightly different, be slightly taller or thinner, or have a different hair color.
These sorts of differences in physical appearance can also happen in cases of IUGR or selective growth restriction, where one twin receives more nutrition than the other in the womb.
The proof is in the prints
Even if your twins split later and, therefore, look much more alike than twins who split earlier in the womb, there is still a definitive way to distinguish between the two of them.
Their fingerprints.
One of the first things an investigative team does when a crime is committed is dust for fingerprints, and the reason for this is that everybody's fingerprints are different—even identical twins.
Their almost-identical DNA provides the general genetic blueprint for the overall look of their fingerprints—the layout of the loops, the arches, the whorls.
But the precise prints and their distinguishable details (the raised ridges and the recessed furrows) are shaped by their unique experience in the environment of the womb.
But the precise prints and their distinguishable details (the raised ridges and the recessed furrows) are shaped by their unique experience in the environment of the womb.
Fluctuations in each of their amniotic fluid pressure, their umbilical cord length and blood flow, their access to nutrition, the rate of finger growth at the end of the first trimester, and even the movement of each fetus, contributes to the final look of their fingerprint.
So, while monozygotic twins have fingerprints that may be quite similar, they're not identical. According to Washington State Twin Registry, where the skin ridges meet, divide into branches, or end are different, thanks to how their genes interact in the developmental environment of the womb.
Fingerprint patterns start developing around 13 weeks' gestation, and before 20 weeks' along, they're finalized and set for life.
According to the University of Maryland, Baltimore County (UMBC), our fingerprints are created when our "deeper layer of skin, called the basal layer, starts growing faster than the layers above it, causing the smooth layer of skin to buckle and fold. The lower layer scrunches and bunches beneath the outside layer, and these folds eventually cause the outer layer of skin to fold, too."
UMBC says the pattern of our prints are encoded deep below our skin's surface layer, which means that even if you have a major skin injury, your fingerprints will come back when the outer layer heals.
I can personally confirm that this is true. I had a very serious finger injury four years ago, and I wondered if I'd have any fingerprints once the skin came back. It took a long time to heal, but when it did, it healed fully, prints and all.
Different people, different prints
While identical twins share a lot of things, one thing they don't share is their fingerprints.
Identical twins can share almost 100 percent of their DNA, but their fingerprints don't start forming until several weeks after the single zygote splits. Fingerprint patterns start developing around nine weeks' along, with final prints being set in stone by 20 weeks'.
Each person's fingerprints are impacted by individual environmental factors each fetus experiences in the womb, which means that while genetics play a role in their general look, everyone's fingerprints are totally unique to them.
Did you think identical twins would have identical fingerprints? Let us know in the Comments section below or connect with us on Instagram to share your thoughts!
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