Question: How to find a ncbi nucleotide entry in the FTP site
gravatar for leontp587
4.2 years ago by
United States
leontp5870 wrote:


I have a big list of ncbi accession numbers for plasmids that I want to grab the sequences to. Examples:


These are all plasmids, but none of them seem to show up under the folder. Anyone know why?

How can I find these records in the FTP site? I tried to use an FTP program to search for a file with A78782 in its name but this would take days given how big the FTP site is.

Sorry for this very newbie question. I'm completely new to this.

I know it's possible to use e-utils, but I have several tens of thousands of these accession numbers, so FTP would seem faster.

genome • 1.8k views
ADD COMMENTlink modified 4.2 years ago by 5heikki8.4k • written 4.2 years ago by leontp5870
gravatar for Neilfws
4.2 years ago by
Sydney, Australia
Neilfws48k wrote:

To answer "anyone know why" first, take a look at the README in FTP genomes which includes this line:

     Plasmids: sequence and annotation of RefSeq plasmids

So only plasmids with RefSeq accessions are found there; you have GenBank accessions.

I'm pretty sure that you will not find a separate GenBank division for plasmid sequences in the FTP site. If you don't want to mirror GenBank locally or use eutils, you could try Batch Entrez, then Send to -> File -> Fasta.


ADD COMMENTlink written 4.2 years ago by Neilfws48k
gravatar for 5heikki
4.2 years ago by
5heikki8.4k wrote:

Your best bet is probably eutils. You can retrieve 500 seqs with every call so even several tens of thousands isn't such a big deal. Here $1 is a list of GIs and Entrez Direct is assumed to be in $PATH:

split -l 500 -a 5 $1 input.
for f in input.*
IDs=$(cat $f | tr "\n" ",")
epost -db nuccore -id $IDs | efetch -format fasta > $f.output
cat *.output > plasmids.fna
#Everything worked out? rm input.* output.*
ADD COMMENTlink modified 4.2 years ago • written 4.2 years ago by 5heikki8.4k
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