backtranseq takes a protein sequence and makes a best estimate of the likely nucleic acid sequence it may have come from.

Here is a sample session with backtranseq. Note that this is a human protein, so the default (human) codon frequency file is used:

% backtranseq
Back translate a protein sequence
Input sequence: sw:opsd_human
Output sequence [opsd_human.fasta]:

Here is a session using a drosophila sequence and codon table:

% backtranseq -cfile Edrosophila.cut
Back translate a protein sequence
Input sequence: sw:ach2_drome
Output sequence [ach2_drome.fasta]:

Mandatory qualifiers:

[-sequence] (sequence)

Sequence USA.

[-outfile] (seqout)

Output sequence USA.

Optional qualifiers:

-cfile (codon)

Codon usage table name.