Tutorial addition: Store ASV sequences in phyloseq object

[mikemc]

At the end of the DADA2 tutorial, when creating the phyloseq object, it is useful to add a DNAStringSet object (to be accessed by the refseq function) to keep track of the ASV sequences.

sequences <- Biostrings::DNAStringSet(taxa_names(ps))
names(sequences) <- taxa_names(ps)
ps <- merge_phyloseq(ps, sequences)
ps

Now we can rename our ASVs to something more convenient in downstream analysis, while automatically retaining the corresponding unique sequence identifier:

taxa_names(ps) <- paste0("ASV", seq(ntaxa(ps)))