DATA: I have analysed Commander Riker's DNA structure. A synthetic T-cell has invaded his genetic codes. This T-cell has begun to activate his latent introns.
PICARD: Introns?
DATA: They are genetic codes which are normally dormant. They are evolutionary holdovers, sequences of DNA that provided key behavioural and physical characteristics millions of years ago, but are no longer necessary. For instance, Counsellor Troi's gill slits and other amphibious characteristics were derived from introns which still contain amphibious codes.
PICARD: So these introns are causing her DNA to re-combine in an earlier configuration?
DATA: That is correct. In her case, the DNA has created an amphibious lifeform which became extinct over fifty million years ago.
PICARD: And Commander Riker's introns are changing him into what appears to be one of the earlier hominids.
DATA: Yes, sir. I would say Australopithecine. Each of these stages is another link in the evolutionary chain which stretches back to the origins of all lifeforms on Earth. Because introns can include genetic material from many different species over millions of years of evolution, it is possible that a wide variety of transformations is occurring among the crew.
PICARD: What about those crewmembers who are not from Earth?
DATA: All humanoid life has a similar genetic pattern. The virus should work on non-human crewmembers in the same way. They are each de-evolving to earlier forms of life on their homeworlds. I feel I must inform you, sir, you have also been infected by the intron virus.
PICARD: How long before I begin to change?
DATA: According to my calculations, within the next twelve hours, you will begin to exhibit the first signs of your eventual transformation.
