subfunctionalization
This term is a highly specialized technical descriptor used almost exclusively within evolutionary biology and genetics. It describes a specific outcome of gene duplication where the ancestral gene's roles are split between two copies, preventing either from being lost to mutation because both now perform essential, albeit limited, tasks.
In a scientific context, it is often contrasted with neofunctionalization, where one duplicate gene evolves an entirely new function while the other maintains the original. Because it refers to a specific biological mechanism, it is used in formal academic papers and textbooks rather than general conversation.
Meanings
The evolutionary process by which two duplicate genes partition the original functions of a single ancestral gene, such that each duplicate gene specializes in a subset of the original functions.
After the gene duplication event, subfunctionalization occurred, leaving each daughter gene to handle only a portion of the ancestral protein's expression pattern.