Everything that we eat today has been improved through some sort of breeding process. Anytime you do this, you introduce not only the genes that you know, but some that are not characterized.
In journalism just one fact that is false prejudices the entire work. In contrast, in fiction one single fact that is true gives legitimacy to the entire work. That's the only difference, and it lies in the commitment of the writer. A novelist can do anything he wants so long as he makes people believe in it.