# What causes fingerprints

**URL:** <https://boards.straightdope.com/t/what-causes-fingerprints/54373>\
**Category:** Factual Questions\
**Created:** [February 13, 2001, 10:45pm UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373 "2001-02-13T22:45:17Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![zev\_steinhardt](https://avatars.discourse-cdn.com/v4/letter/z/97f17d/32.png) [@zev\_steinhardt](https://boards.straightdope.com/u/zev_steinhardt)\
**Post date:** [February 13, 2001, 10:45pm UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373/1 "2001-02-13T22:45:17Z")

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I used to think that DNA determined what a person’s fingerprints looked like. However, I recently found out that identical twins (who have the same DNA) do not have different fingerprints. That being the case, what causes the patterns that I have on my fingers and what makes them unique?

Zev Steinhardt

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**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\
**Post date:** [February 13, 2001, 10:51pm UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373/2 "2001-02-13T22:51:23Z")

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Your post doesn’t make sense. Your DNA **does** determine them. That’s why identical twins with the same DNA **do not** have **different patterns**. Same DNA same fingerprint.

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**Author:** ![zev\_steinhardt](https://avatars.discourse-cdn.com/v4/letter/z/97f17d/32.png) [@zev\_steinhardt](https://boards.straightdope.com/u/zev_steinhardt)\
**Post date:** [February 13, 2001, 11:08pm UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373/3 "2001-02-13T23:08:53Z")

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> [@](#):
>
> \*Originally posted by Hail Ants \*  
> \*\*Your post doesn’t make sense. Your DNA **does** determine them. That’s why identical twins with the same DNA **do not** have **different patterns**. Same DNA same fingerprint. \*\*

Thanks for catching that **Hail Ants** [sub]I can’t believe I did that[/sub].

Let me try again:

Identical twins have **different** fingerprints, but the same DNA. So, obviously, fingerprint patterns do not come from DNA. That being the case, where do they come from?

Zev Steinhardt

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**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\
**Post date:** [February 13, 2001, 11:52pm UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373/4 "2001-02-13T23:52:35Z")

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I read somewhere that identical twins’ fingerprints are very close but not identical, which is confirmed by what is said at [this page](http://www.walker.atfreeweb.com/Reading/fingerprints.htm):

> [@](#):
>
> When doctors state that twins have the same fingerprints, they are referring to the class characteristics of the general ridge flow, called the fingerprint pattern. These loop, arch and whorl ridge flow patterns have nothing to do with the individual characteristics used to positively identify persons.

The page also mentions that cloned monkeys have different fingerprints, and that fingerprints are formed at approximately three or four months during the fetal development process.

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**Author:** ![manhattan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/manhattan/32/7_2.png) [@manhattan](https://boards.straightdope.com/u/manhattan)\
**Post date:** [February 14, 2001, 12:43am UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373/5 "2001-02-14T00:43:44Z")

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[This guy](http://www.straightdope.com/columns/980821.html) had an interesting take on the subject.

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**Author:** ![Arnold\_Winkelried](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Arnold\_Winkelried](https://boards.straightdope.com/u/Arnold_Winkelried)\
**Post date:** [February 14, 2001, 1:14am UTC](https://boards.straightdope.com/t/what-causes-fingerprints/54373/6 "2001-02-14T01:14:54Z")

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So that’s where I read it originally! (hanging head in shame) I’ve been upstaged by the ever-knowledgeable **manhattan**.