The tool formats DNA or RNA so only characters representing DNA or RNA nucleotides will be recognized. DNA: Adenine (A), Cytosine (C), Guanine (G) and Thymine (T). RNA: Adenine (A), Cytosine (C), Guanine (G) and Uracil (U). This tool does not distinguish between the orientation of DNA or RNA, sequences can be entered in a 5' to 3' or 3' to 5' direction.