# No piRNA or other antisense small RNA in Block Cluster Test?

**URL:** <https://help.galaxyproject.org/t/no-pirna-or-other-antisense-small-rna-in-block-cluster-test/9949>\
**Category:** Uncategorized\
**Tags:** transcriptomics, rna-seq\
**Created:** [April 24, 2023, 9:16am UTC](https://help.galaxyproject.org/t/no-pirna-or-other-antisense-small-rna-in-block-cluster-test/9949 "2023-04-24T09:16:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Wenjing](https://avatars.discourse-cdn.com/v4/letter/w/9dc877/32.png) [@Wenjing](https://help.galaxyproject.org/u/Wenjing)\
**Post date:** [April 24, 2023, 9:16am UTC](https://help.galaxyproject.org/t/no-pirna-or-other-antisense-small-rna-in-block-cluster-test/9949/1 "2023-04-24T09:16:18Z")

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1. When I perform Block Cluster Test with my small RNA-seq data, I only see miRNA, tRNA and some sno RNA but no piRNA or other smallRNA. Does anybody know why?

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**Author:** ![jennaj](https://sea2.discourse-cdn.com/flex020/user_avatar/help.galaxyproject.org/jennaj/32/27_2.png) [@jennaj](https://help.galaxyproject.org/u/jennaj)\
**Post date:** [May 2, 2023, 7:33pm UTC](https://help.galaxyproject.org/t/no-pirna-or-other-antisense-small-rna-in-block-cluster-test/9949/2 "2023-05-02T19:33:15Z")

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Welcome, @Wenjing

Is this the tutorial you are following? [Small Non-coding RNA Clustering using BlockClust](https://training.galaxyproject.org/training-material/topics/transcriptomics/tutorials/small_ncrna_clustering/tutorial.html). Tutorial data is a sub-sample of full data and while attempts are made to provide representative sub-samples, that isn’t always perfect.

Maybe the publication linked at the bottom of the tool form will help more? It is available open source. [BlockClust: efficient clustering and classification of non-coding RNAs from short read RNA-seq profiles | Bioinformatics | Oxford Academic](https://academic.oup.com/bioinformatics/article/30/12/i274/385482)

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**Author:** ![Wenjing](https://avatars.discourse-cdn.com/v4/letter/w/9dc877/32.png) [@Wenjing](https://help.galaxyproject.org/u/Wenjing)\
**Post date:** [May 17, 2023, 5:31am UTC](https://help.galaxyproject.org/t/no-pirna-or-other-antisense-small-rna-in-block-cluster-test/9949/3 "2023-05-17T05:31:26Z")

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Thanks a lot! I will have a look.