A fragment of a single strand of DNA, built of the nucleobases cytosine and guanine, can be imprinted in a polymer—this has been shown by chemists from Warsaw, Denton and Milan. The resulting artificial negative, with a record-long length, functions chemically like a normal strand of deoxyribonucleic acid. This achievement finally confirms the possibility of creating polymer imprints of DNA, functionally corresponding to DNA fragments containing all four nucleobases.