# Tracing the origin of 'Feature ID / OTU ID" name

**URL:** https://forum.qiime2.org/t/tracing-the-origin-of-feature-id-otu-id-name/14066
**Category:** User Support
**Tags:** ids, otus, feature-table
**Created:** [March 15, 2020, 4:27pm UTC](https://forum.qiime2.org/t/tracing-the-origin-of-feature-id-otu-id-name/14066 "2020-03-15T16:27:47Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Claudio21](https://forum.qiime2.org/letter_avatar_proxy/v4/letter/c/7cd45c/32.png) [@Claudio21](https://forum.qiime2.org/u/Claudio21)
#### Post date: [March 15, 2020, 4:27pm UTC](https://forum.qiime2.org/t/tracing-the-origin-of-feature-id-otu-id-name/14066/1 "2020-03-15T16:27:47Z")

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Hello there,  
i have a really simple and stupid question to ask. During the QIIME2 analysis, when a Feature[table] .qzv file is displayed in QIIME2 view webpage, the first column sums up the 'Feature ID' or 'OTU ID' of the current analysis. My question is: how does this alpha-numeric code is generated? It is specific to each OTU that you are observing, but is it just a random code that can vary at each analysis? In other words, does this correspond to a specific OTU level (e.g. Genus) even without the corresponding taxonomy?

I hope my question was pretty clear, in other case I will try to explain it in a better way!

Thanks in advance!

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### Author: ![timanix](https://forum.qiime2.org/user_avatar/forum.qiime2.org/timanix/32/17879_2.png) [@timanix](https://forum.qiime2.org/u/timanix)
#### Post date: [March 15, 2020, 5:19pm UTC](https://forum.qiime2.org/t/tracing-the-origin-of-feature-id-otu-id-name/14066/2 "2020-03-15T17:19:10Z")

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Hi!  
I think this thread is answering your questions

> [@How are ASV IDs generated?](https://forum.qiime2.org/t/how-are-asv-ids-generated/6075):
>
> I'm curious as to how the IDs assigned to ASV (e.g. 00137a07c917bab6cfcb89a796f69a38) are generated as I'm trying to merge multiple DADA2 feature tables together. Is it some sort of hash of the representative sequence? Can the ID be guaranteed to be the same for independent DADA2 runs assuming the representative sequence is the same between those runs? Can I assume the reverse-complement of the representative sequence is always guaranteed to yield the same ID? Is it safe to assume the represen…

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### Author: ![system](https://forum-qiime2-org.s3.dualstack.us-west-2.amazonaws.com/original/3X/2/1/21af5fe23cb6f4579467c66a9ed94e55274ca7bd.svg) [@system](https://forum.qiime2.org/u/system)
#### Post date: [April 15, 2020, 11:19pm UTC](https://forum.qiime2.org/t/tracing-the-origin-of-feature-id-otu-id-name/14066/3 "2020-04-15T23:19:12Z")

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