@Jasper OP says that for binary they would have decoded it to ascii. I would therefore expect them to decode DNA to either codons or an amino acid sequence. If binary doesn't work for them as a simple alphabet, DNA shouldn't either.
The DNA example doesn't work so well (or works as well as comparisons to binary), as protein sequence is determined by codons (a set of three DNA bases), so there are effectively 64 "letters" rather than four. example