Degeneracy (biology)

In biology, degeneracy describes a relationship between two or more structurally dissimilar components or pathways that can perform similar, effectively interchangeable functions under some conditions but perform distinct functions under others. Because it is a relational property, degeneracy can only be assessed by comparing two or more components rather than by examining a single one in isolation, and the same pair of components may appear redundant under one set of conditions and clearly distinct under another. The concept is unrelated to the older idea of evolutionary degeneration, in which a lineage loses capacities present in its ancestors.