# Total species selected from prescreen: 14

**URL:** <https://forum.biobakery.org/t/total-species-selected-from-prescreen-14/5128>\
**Category:** MetaPhlAn\
**Created:** [April 12, 2023, 7:57am UTC](https://forum.biobakery.org/t/total-species-selected-from-prescreen-14/5128 "2023-04-12T07:57:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![xiaoafei](https://avatars.discourse-cdn.com/v4/letter/x/2acd7d/32.png) [@xiaoafei](https://forum.biobakery.org/u/xiaoafei)\
**Post date:** [April 12, 2023, 7:57am UTC](https://forum.biobakery.org/t/total-species-selected-from-prescreen-14/5128/1 "2023-04-12T07:57:53Z")

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i use humann3 to ran my data(14 GB),but the info show that`Total species selected from prescreen: 14`,it is too small for my data, why it happened?my code as following:  
`humann --input /mnt/qc/F/1H/1H.fastq --output /mnt/gongneng/humann/F/1H --threads 16 --metaphlan-options="--bowtie2db /mnt/shujuku/humann3/metaphlan/v30 --index mpa_v30_CHOCOPhlAn_201901" --diamond-options="--index-chunks 1 --block-size 3" --memory-use maximum`

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**Author:** ![xiaoafei](https://avatars.discourse-cdn.com/v4/letter/x/2acd7d/32.png) [@xiaoafei](https://forum.biobakery.org/u/xiaoafei)\
**Post date:** [April 13, 2023, 12:06pm UTC](https://forum.biobakery.org/t/total-species-selected-from-prescreen-14/5128/2 "2023-04-13T12:06:21Z")

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just now, i use metaphlan4 with humann3, is show `Total species selected from prescreen: 558`, it because the metaphlan4 have more larger database than metaphlan3?

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**Author:** ![aitor.blancomiguez](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/aitor.blancomiguez/32/86_2.png) [@aitor.blancomiguez](https://forum.biobakery.org/u/aitor.blancomiguez)\
**Post date:** [April 14, 2023, 1:25pm UTC](https://forum.biobakery.org/t/total-species-selected-from-prescreen-14/5128/3 "2023-04-14T13:25:54Z")

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Yes, metaphlan 4 has a way larger database in comparison with version 3, please, have a look at our latest publication [Extending and improving metagenomic taxonomic profiling with uncharacterized species using MetaPhlAn 4 | Nature Biotechnology](https://www.nature.com/articles/s41587-023-01688-w)