Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff, Lauren Voge bomb here A. One of life's great marvels is that, much like snowflakes, no two fingerprints are alike. This even goes for identical twins who split from the very same egg and sperm. Although it's not entirely impossible for two fingerprints to match up, the odds are way against it, as in like one in sixty four billion,
definitely not odds you want to take to Vegas. Fingerprints have been studied for millennia, but the FBI today identifies eight primary types of fingerprint patterns. These include four types of loops, two types of arches, one type of whirl, and a so called accidental type, which combines characteristics of all three patterns. But even within those patterns, there's tremendous potential for differences in spacing, depth, angles, m so on.
A prince pattern depends on a potent and unique combination of genetics plus environment. During development. A human skin is easily affected by its environment, and that's why people who spend a lot of time in the sun or doing manual labor tend to have freckled, sunburned, or tougher skin than those who don't. This trait begins in the womb. As a fetis grows, the epidermis and the dermis, that is, the outside and inside layers of the skin, come together naturally,
which produces friction ridges. The ridges get their basic design from the genes of the baby's parents, but fetal cells work at their own individual pace, which causes the skin to grow and stretch and move in different ways. A fetus's budding fingerprints, which develop between thirteen and nineteen weeks of gestation, can also be influenced by the nutrients it's getting, how it's positioned in utero, or even if it rubs
against the wound more umbilical cord. Once a fingerprint is developed, it remains static for the life of the person in question, barring major damage from things like skin diseases, burns, or scarring. Even the most identical of twins can experience individual genetic mutations, making them ever so slightly different from one another. As we develop, signaling pathways help our genes communicate to complete
their individual instructions. These are very sensitive to the womb's environment, which is why identical twins aren't one hundred percent genetically alike, as was previously thought. According to a study published in the journal Cell in twenty twenty three, three different chains of signaling in particular, appear to affect how the fingerprint develops. Some pathways have been found to tamp down the growth
of ridges, whereas others encourage them to develop. A Meanwhile, a third kind affect how big or small ridges or whorls are, and also how they're spaced out. Since everyone's pathways and signals are different, these effect how the fingerprints turn out. In short, abzilion little factors come into play when skin layers first form to create something that's truly
one of a kind. And in case you're curious, just because non human animals might not have fingers per se, that doesn't mean that they don't develop similarly unique traits. For example, cats and dogs have unique noses. The pattern of bumps on the nose of each dog and cat is their own, and much like fingerprints on humans. Today's episode is based on the article why even identical twins have different fingerprints on HowStuffWorks dot com, written by Leo Hoyt.
A Brainstuff is production of iHeartRadio in partnership with HowStuffWorks. Dot com and is produced by Tyler Klang. Four more podcasts My Heart Radio, visit the iHeartRadio app, Apple podcasts, or wherever you listen to your favorite shows.