A functional gene is a specific segment of DNA that encodes a particular protein or RNA molecule that serves a specific purpose within an organism. Synonyms for functional gene include expressed gene, coding gene, and protein-coding gene. These terms refer to genes that are actively transcribed and translated into functional proteins. Other synonyms for functional gene may include active gene, functionally relevant gene, or biologically active gene. These terms highlight the fact that functional genes play a critical role in biological processes and are essential for the proper functioning of cells and organisms. Overall, understanding the synonyms for functional genes can help improve our understanding of genetics and how genes contribute to the diversity of life.