# Rep-seqs length

**URL:** https://forum.qiime2.org/t/rep-seqs-length/20991
**Category:** User Support
**Created:** [October 6, 2021, 2:00pm UTC](https://forum.qiime2.org/t/rep-seqs-length/20991 "2021-10-06T14:00:03Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![Mehrbod\_Estaki](https://forum.qiime2.org/user_avatar/forum.qiime2.org/mehrbod_estaki/32/4001_2.png) [@Mehrbod\_Estaki](https://forum.qiime2.org/u/Mehrbod_Estaki)
#### Post date: [October 6, 2021, 3:47pm UTC](https://forum.qiime2.org/t/rep-seqs-length/20991/2 "2021-10-06T15:47:50Z")

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Hi @Nisha,

> [@Nisha](#):
>
> Are they really merged sequences??

It's hard for us to know the answer to this without seeing some more details about the actual commands you've ran. Especially the stats output of DADA2 which you can visualize and share with us would be very helpful. But, what you are describing is technically possible if there is a complete overlap between your forward and reverse reads. What is the expected overlap and the length of the final merged products?

> [@Nisha](#):
>
> And even if I see them as technical replicates, they should be very few in numbers. So if I filter these sequences on the basis of frequency, they should get eliminated. but I can still see them in my filtered-rep-seqs.qzv.

I guess this again would depend if they are real merged products with full overlap or somehow erroneous products. What were your filtering parameters?

> [@Nisha](#):
>
> Is there any way to remove low length sequences? or any other suggestion?

There are a couple of ways of doing this:

1. Using the [RESCRIPt plugin](https://forum.qiime2.org/t/processing-filtering-and-evaluating-the-silva-database-and-other-reference-sequence-data-with-rescript/15494) with its plethora of useful actions.
2. This neat little [trick](https://forum.qiime2.org/t/filtering-out-asvs-from-dada2-based-on-length/9217/4) using `feature table filter seqs`

Hope this helps!

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