This was the usage in question. It has actually appeared in at leat one professional journal, maybe more. The duplicate in the published case was apparently natural.
"This was the usage in question. It has actually appeared in at leat one professional journal, maybe more. The duplicate in the published case was apparently natural."
This could happen naturally, although it would be rare. It is a proposed mechanism in the concept of enzyme recruitment, whereby a gene is duplicated, one remains "wild type" with one function while the other undergoes modification for a new function. Then both functions will be expressed simultaneously, from what was once two of the same genes. Gene duplication doesn't last very long if there is no selective pressure to keep it. Mutation rates in bacteria are just too high.
But you are right, "recessive" is for polyploids.