Every feature in only 1 sample

[Muhammad_Zeeshan_Akr (Muhammad Zeeshan Akram)]

Hi,

I have sequencing data (300 bp) of V3-V4 region. I received this data from illumina through casava files means every zip file is already named with R1 and R2. I did not receive any barcode file from seq facility. I am not sure it is multiplexed or demultiplexed. I imported this data to qiime. The process was smooth and checked the read quality. AFter this, i used dada2 for denoising of only forward reads as i was facing problem with merging of both forward and reverse reads due to truncation length. After denoisng, i receive more than 900 features and 1 million frequencies. I was happy that i got good features as comapre to merged reads but then i checked that all the features belong to one sample.

I do not understand why it happens like this and how can i resolve this problem.

[colinbrislawn (Colin J Brislawn)]

Hello Muhammad,

Did you search the forums for similar issues? I found this thread, which also shows each feature in one sample because the barcodes were included in the reads. Each ASV was contaminated with a per-sample barcode, resulting in per-sample ASVs.

Let us know if you have any questions about how to trim out barcodes from your reads.