# Identical Twins DON'T have identical genetic codes?

**URL:** <https://boards.straightdope.com/t/identical-twins-dont-have-identical-genetic-codes/608175>\
**Category:** Factual Questions\
**Created:** [January 2, 2012, 9:13pm UTC](https://boards.straightdope.com/t/identical-twins-dont-have-identical-genetic-codes/608175 "2012-01-02T21:13:57Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![Harmonix](https://avatars.discourse-cdn.com/v4/letter/h/3ec8ea/32.png) [@Harmonix](https://boards.straightdope.com/u/Harmonix)\
**Post date:** [January 4, 2012, 3:33am UTC](https://boards.straightdope.com/t/identical-twins-dont-have-identical-genetic-codes/608175/21 "2012-01-04T03:33:17Z")

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I haven’t seen it mentioned yet, but I also believe that the [VDJ regions](http://en.wikipedia.org/wiki/V%28D%29J_recombination) are also different between twins. These are regions of DNA which code for the diversity of your immune system. I can not recall the exact details, but I believe they are randomly recombined in every individual.

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**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\
**Post date:** [January 4, 2012, 3:44am UTC](https://boards.straightdope.com/t/identical-twins-dont-have-identical-genetic-codes/608175/22 "2012-01-04T03:44:25Z")

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> [@Harmonix](#):
>
> I haven’t seen it mentioned yet, but I also believe that the [VDJ regions](http://en.wikipedia.org/wiki/V%28D%29J_recombination) are also different between twins. These are regions of DNA which code for the diversity of your immune system. I can not recall the exact details, but I believe they are randomly recombined in every individual.

Yes, they were discussed in some detail in at least one of the above-linked old threads.

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**Author:** ![quenda](https://avatars.discourse-cdn.com/v4/letter/q/b5e925/32.png) [@quenda](https://boards.straightdope.com/u/quenda)\
**Post date:** [January 4, 2012, 4:39am UTC](https://boards.straightdope.com/t/identical-twins-dont-have-identical-genetic-codes/608175/23 "2012-01-04T04:39:08Z")

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> [@China\_Guy](#):
>
> IIRC from when my wife was pregnant with twins, identical twins share around 95% of the same genetic code.

Humans share that much with chimps.

> **[National Geographic](https://www.nationalgeographic.com/)**
>
> Explore National Geographic. A world leader in geography, cartography and exploration.

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