Alumnus of Freie Universität Berlin – Michael Grünstäudl, PhD » Blog Archiv » Few-liner: Batch download of DNA sequences from NCBI

Few-liner: Batch download of DNA sequences from NCBI

The wonders of entrez

Today I found myself in need of a script to download dozens of DNA sequences submitted to NCBI Nucleotide. The sequences in questeion were stores in file input.txt.

$ cat input.txt
  Liriope_muscari_USACult,JX080424
  Dracaena_adamii_IVORYCOAST,JX080436
  ...

Here is how I did it:

$ INF=input.txt
$ for line in $(cat $INF); do
    SEQNAME=$(echo "$line" | awk -F',' '{print $1}')
    ACCNUM=$(echo "$line" | awk -F',' '{print $2}')
    FULLNAM=$(echo ">${SEQNAME}_${ACCNUM}")
    SEQ=$(esearch -db nucleotide -query "$ACCNUM" | efetch -format fasta | tail -n +2)
    echo -e "$FULLNAM\n$SEQ" >> out.txt
  done