No two people have identical fingerprints, not even twins. But do twins have broadly similar prints?
Fingerprints come in three types, loop, whorl and arch. Arches may be plain or tented. Loops may be radial or ulnar, depending on which way the tail points. Whorls have several subcategories.
So, if on twin has an arch on his right index finger, would the other twin have the same? If so, how different or similar are they? Is it possible for one to have a plain arch, and the other a tented arch? Or would they have the same type of arch?
I’ve heard that some identical twins are mirror images. So, if one twin has an ulnar loop on his right thumb, does the other have a radial loop on his left thumb?
According to online sources, broadly similar prints are common but not guaranteed. Fingerprints are determined in the womb by genetic and environmental factors. This blasts the hell out of a hoary science fiction cliche: clones would have different fingerprints from their source.
I’m too lazy to check, given my eyesight - do people have all the same pattern on every finger? Would that be an indication of overall shape being determined genetically?
On a somewhat related point: I know cloned horses, dogs, and cats don’t have identical color patterns. They will inherit the same colors, but they won’t match exactly. Since identical twins are more or less clones of each other, I’d expect the same from fingerprints.
Randomized color patterns, like on a calico cat, can sometimes be the result of a sort of mosaicism. Female mammals have two X chromosomes, but since we’re evolved for one X to be enough (for the sake of males), in females, one X is deactivated in each cell. Which one, though, is determined more or less randomly, at a stage in development where the embryo consists of only a small number of cells. If the two Xs carry genes for different fur colors, then you end up with splotches of each color, all from cells descended from one of those cells. That’s why, barring chromosomal abnormalities like XXY, calico cats are always female.
What’s the purpose of fingerprints anyway. I heard it’s for better gripping but seeing how small they are this seems dubious. And why the need for intricate patterning if that’s all it is?
“Purpose” implies deliberate and intelligent design, and I feel like they came about as pure happenstance. They do have the effect of making things you hold slip less.
Oh thank the stars. Now we can figure what twin is getting into the cookie jar.
Really, I looked at the twins fingers, which to tell the truth I didn’t wanna touch the little germ carriers filthy hands. They are as different as their sisters are.
No matchy matchy.
They do have matching moles. One has a birthmart on his butt, the other does not.
Now that they growing into proper little boys, with baby hair all gone, one has the cutest cowlick. The other does not.
Recent research indicates that finger patterns are related - not entirely independent. This is new information: it was believed that each finger pattern was independent.
A “single good fingerprint” is not enough to unambiguously identify a person. If you have all 10 prints, you perhaps have enough information to identify a person “beyond reasonable doubt”, but even so, there are known cases where different people have the “same fingerprint set”. Properly used, fingerprints identify a person of interest, not proof of identity
Knowing that the finger patterns are related, we may make two observations: a set of prints actually contains less information than 10 independent fingers: and a set of 9 prints can be used to predict something about the missing 10th finger print. These observation may eventually lead to improved automatic fingerprint identification algorithms. Used for evidence, not for conclusive independent proof.
As an older person with dry skin whose work involves handling things sufficiently to wear down my fingerprint ridges… yes, they do slightly improve grip.
Also, for a more modern concern, if they ridges get too worn down fingerprint readers won’t be able to discern them anymore, which can get annoying for items requiring biometric access.
Not at all. I think you are confusing the often misunderstood notion that ‘need’, somehow, drives evolution. I’m under no such misconception
Only in the sense that proto-fingerprints were an probably a genetic mutation. But the fact that mutations were ultimately helpful (somehow) ensured that they not only remained, ultimately being the default in the species, but evolved into higher complex designs.
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Sure, now that we have slick peanut butter jars to open, I can see how they might help, but millions of years ago it seems that most things like tree bark and stones were rougher than fingerprint ridges.
As tree-climbing primates also have “fingerprints” that assumption might not hold up. While the bark near the base of a tree is generally (but not always) rough, the branches higher up are often much smoother.
Also, if you’ve ever watched someone flint knapping, the stones frequently start out pretty smooth, often taken from water sources, and would require a very firm grip to manipulate while shaping them, especially in the days before protective gloves and other gear.
Likewise, being able to firmly and securely hold onto things like smooth-skinned fruits and nuts might be useful.
For whatever reason, our ancestors with fingerprints survived while those without did not, so either they have been very useful or, if they’re not useful, they weren’t detrimental enough to be eliminated.