Unique body parts

by Sandee LaMOtte

Published 8:14 PM ET, Thu November 19, 2015
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Move over fingerprints. From your ears to your toes, many of your body parts make you uniquely special. And all of them are being investigated as a way to identify you from others in a crowd. Rob Daly/Caiaimage/Getty Images/Caiaimage
The ridges, bumps and shape of your outer ear are so unique that your ear may soon be one of the best ways to identify you. According to University of Southampton biometrics expert Mark Nixon, studies have shown up to 99.6% accuracy when ears were scanned using computer software that recreates their position, scale and rotation. That's as accurate as a fingerprint and you don't have to ink up first. Shutterstock
The pattern of your iris differs in each eye. This even holds true for identical twins. How does that happen? As the developing fetus opens and shuts its eyes in utero, iris tissue tightens and folds randomly, so no two can be the same. Shutterstock
Researchers are trying to look deep into your eyes from a safe distance, like when a police officer stops a car and needs to identify the occupant. "A police officer could identify who the driver is before approaching," says Marios Savvides of Carnegie Mellon's CyLab. "Long-range iris recognition can [also] help identify victims of human trafficking or abduction and alert authorities." Shutterstock
See all those tiny bumps and ridges? "It's the different distribution of size and shape," says University of Notre Dame biometrics expert Kevin Bowyer, that makes your tongue unique to you, just like fingerprints. But no one expects you to start inking up your tongue for an ID print anytime soon. "Gosh, the user acceptance of that is going to be really, really low," says Bowyer with a chuckle. Shutterstock
Researchers are fast at work analyzing the way you move so you can be identified in a crowd. "We look at the motion of the body and the body parts, then measured those with a computer to get a set of numbers," says University of Southampton biometrics expert Mark Nixon. "And as long as we get the same set of numbers for each person, we can achieve recognition."
No one else has your exact fingerprints, even your identical twin. How can that be? It's all about the random way you used your fingers while the tips were developing in the womb. The density of your mom's amniotic fluid, how much you move, and your position in the womb are all thought to affect how those unique ridges formed on your fingers. Shutterstock
Think of your DNA as four Legos that like to play in pairs along a spiral staircase called a double helix. Those pairs (A and T; C and G) form building blocks of code called genes that become the blueprint for your hair, eyes, body shape and everything else that makes you unique. There are almost 20,000 human genes, created from about 3 billion bases, so it's easy to see why no other human will have the exact same pattern of DNA. Shutterstock
Breakthrough studies in the last year show even identical twins have different DNA. Using second generation genome sequencing, says Bowyer, "If you do a more detailed and deeper level construction of DNA, you find that once that fertilized egg splits there are random mutations that are happening and that can be used to identify differences between twins." Shutterstock
Your voice is another way to identify you, and we have unique characteristics formed by the length of our vocal tract, the frequency and intensity of our vocal quality, and how we've learned to speak. Because it's so easy for someone to mimic another voice, you have to use a computer to tell the differences, and science is working hard on that. shutterstock
The Pentagon is hard at work trying to analyze your personal smell, the one that's linked to your genetics. It's believed dogs recognize their owners in that manner, and the military is trying to wade through the more than 300 compounds that can produce a human's smell. Shutterstock
The pattern of blood vessels displayed on the retina at the back of your eye is a very precise snapshot of your nervous system — unique to you. Ophthalmologists can see telltale first signs of diabetes, multiple sclerosis, high blood pressure, even brain health. Smart phones are taking the technology to Third World countries. Courtesy Peek
Even our unique bits change as we age, which makes it challenging for those who want to identify us.
"Is there anything that never changes at all? I wouldn't say that," says Bower. "But for things we think are pretty stable, or we know how they age, generally we have some sort of idea through aging recognition techniques."