# expected sequences in custom database and reads, but not matching in taxonomy table **URL:** https://forum.qiime2.org/t/expected-sequences-in-custom-database-and-reads-but-not-matching-in-taxonomy-table/24962 **Category:** User Support **Tags:** taxonomy, dada2 **Created:** [December 8, 2022, 5:31pm UTC](https://forum.qiime2.org/t/expected-sequences-in-custom-database-and-reads-but-not-matching-in-taxonomy-table/24962 "2022-12-08T17:31:00Z") **Posts on this page:** 1 **Showing post:** 3
### Author: ![SoilRotifer](https://forum.qiime2.org/user_avatar/forum.qiime2.org/soilrotifer/32/21071_2.png) [@SoilRotifer](https://forum.qiime2.org/u/SoilRotifer) #### Post date: [December 9, 2022, 5:45pm UTC](https://forum.qiime2.org/t/expected-sequences-in-custom-database-and-reads-but-not-matching-in-taxonomy-table/24962/3 "2022-12-09T17:45:32Z")
Hi @jrdupuis, welcome to :qiime2:! Have you tried [this approach](https://forum.qiime2.org/t/using-rescripts-extract-seq-segments-to-extract-reference-sequences-without-pcr-primer-pairs/23618) to make your database? I explicitly use the trnL marker gene as an example (though slightly different primer pair). Some general thoughts and other highlights from the tutorial: - You'll notice the `--p-query` is far more explicit. This is to make sure I am including the groups I would like to keep, and excluding spurious reference data. - Also, relying solely on PCR / Sequencing primer searches can be problematic. - Taxonomic miss-annotation is a common problem in reference databases and can affect the resulting _consensus taxonomy_, and may need to be corrected. For this reason we provide the [edit-taxonomy](https://forum.qiime2.org/t/processing-filtering-and-evaluating-the-silva-database-and-other-reference-sequence-data-with-rescript/15494#heading--sixteenth-header) command within RESCRIPt, to help mitigate these issues. Perhaps run through the tutorial and let us know if this helps? -Cheers! -Mike --- _[View the full topic](https://forum.qiime2.org/t/expected-sequences-in-custom-database-and-reads-but-not-matching-in-taxonomy-table/24962)._