sub get_all_seqs{
    my $protein = shift;
    #print "protein = $protein\n";
    my @aas = split(//, $protein);
    my %Deg_codons = get_degenerate();    
    my @codons = @{$Deg_codons{$aas[0]}};
    my %SEQ = map { $_ => 1 } @codons;

    foreach my $aa (@aas[1..$#aas]) {
        foreach my $seq (keys %SEQ) {
            foreach my $codon (@codons) {
                $SEQ{$seq.$codon} = 1;
            }
            delete $SEQ{$seq};
        }    
    }

    return sort keys %SEQ;    
}