uncomplemented

Uncomplemented is an adjective used to describe something that lacks a complement or the usual partnering element that would complete it. The specific sense depends on disciplinary usage: in many scientific contexts, a complement is a partner that completes a structure, interaction, or expression.

In genetics and molecular biology, uncomplemented often refers to nucleic acid regions that do not have their standard complementary sequence for base pairing under the conditions considered. For example, single-stranded DNA or RNA regions may be uncomplemented to a reference strand, or regions with mismatches that resist stable pairing. Such regions can behave differently in replication, transcription, or folding.

In linguistics, complement is a phrase that completes the meaning of a predicate or a verb. An uncomplemented construction is one in which an obligatory complement is absent under a given analysis. This usage is theory-dependent, and many verbs function without a required complement in common usage.

In chemistry or materials science, uncomplemented can describe species that are not paired with an anticipated partner in a reaction, crystal, or lattice, such as a site that remains unsatisfied by a counterion or ligand.

The term is distinct from complementary, which indicates an actual pairing or mutual completion. Uncomplemented discussions often appear in discussions of base pairing, syntactic theory, and coordination chemistry, among others.