Nootide

Nootide is a term used in speculative biology and certain theoretical discussions to denote a hypothetical monomer that would serve as the basic unit of information storage in polymers other than DNA or RNA. In this context, a nootide is envisioned as a modular unit composed of a sugar-like backbone, a heterocyclic base, and a linking group that enables chain growth, analogous to a nucleotide but not tied to the chemical structures of natural nucleotides. The concept is not part of established chemistry or molecular biology; it remains a hypothetical construct used to explore ideas about non-canonical biopolymers and abiotic information storage.

Literature on nootides varies in its specifics, reflecting their fictional or theoretical status. Some treatments describe diverse backbones that could confer different folding, pairing, or replication properties, while others discuss nootides with alternative linking chemistries that would enable information processing in unconventional substrates. The term is sometimes employed in thought experiments about how life's information carriers could differ from DNA and RNA, or in discussions of synthetic biology and nanotechnology aiming to expand the range of information-carrying polymers.

Relationship to other terms: nootide is distinct from nucleotide and is not widely standardized, with no single agreed-upon chemical structure. The concept shares kinship with non-natural information carriers such as xeno-nucleic acids (XNA) and peptide nucleic acids (PNA), but it remains a speculative category rather than a defined chemical family.