SILVA 16S database

[AndreaC (Andrea Colautti)]

Hi,

@SoilRotifer

You can simply download the classifier made for that version of . On any of the documentation pages you'll see a drop menu on the upper left. Simply select the version of you have and download the classifier from the data resources page listed on the left. You'll have to keep telling the web site to take to you the content for that version and not the latest version of

I can't figure out which drop-down menus you are referring to.

Training Silva database

Hello there, I have a question for database training. In extract reference reads, is it OK that no truncation of sequences? In the Qiime2Docs (https://docs.qiime2.org/2020.2/tutorials/feature-classifier/), It suggests truncating the database sequence length based on QC results of sequencing results (120 base). Meaing this that, should train 16S database everytime for analysis based on sequencing quality? Thanks always, I learned a lot here. Best, Jun

I read in several posts that "If you're doing 16s sequencing rarely, or this is your first time, a pre-trained, full length classifer is fine." however, I notice significant differences between using a full database versus just one 16s.

For example in this case with kraken

while for the data provided processed with silva database and qiime2, the results are very close to those I get through kraken2 and silva 16S, while if I try to replicate the analysis with qiime2 and the complete Silva database, I get % totally different.

What database should I believe?