Reprint of: Non Canonical Genetic Material.

• Xenobiotic Nucleic Acids (XNAs) are highly potential biotechnological and therapeutic tool. • XNAs possess enhancing thermal and biological stability and increasing chemical diversity. • XNAs act as alternative genetic material by transferring information in vitro and in vivo. • An unnatural base pair can increase information space by introducing an additional coding element. • Replacement of the bacterial genome by non-canonical nucleotides lead to a chemically modified organism (CMO) of broad applications. To increase the scope of natural biosystem, nucleic acids have been intensively modified. One direction includes the development of a synthetic alternative to the native DNA and RNA, denoted Xenobiotic nucleic acids (XNAs) that are able to store and transfer genetic information either by base-modification or backbone-modification. Another line of research aims to develop alternative third base pair additional to natural A:T and G:C. These unnatural base pairs (UBPs) can store increased information content encoded in three base pairs. This review outlines the recent progress made towards XNA and UBP applications as new components of the genomic DNA as well as biostable aptamers. New achievements in the replacement of a bacterial genome by unnatural non-canonical nucleotides are also described. [ABSTRACT FROM AUTHOR]