Evolving genomic metaphors: a new look at the language of DNA.

Recent genome-sequencing efforts have confirmed that traditional "good-citizen" genes (those that encode functional RNA and protein molecules of obvious benefit to the organism) constitute only a small fraction of the genomic populace in humans and other multicellular creatures. The rest of the DNA sequence includes an astonishing collection of noncoding regions, regulatory modules, deadbeat pseudogenes, legions of repetitive elements, and hosts of oft-shifty, self-interested nomads, renegades, and immigrants. To help visualize functional operations in such intracellular genomic societies and to better encapsulate the evolutionary origins of complex genomes, new and evocative metaphors may be both entertaining and research-stimulating.