So. If this naturally caffiene-free arabica tastes good, that's a very good thing in the world of coffee. And who knows, maybe we can put the decaf gene into other types of coffee, like kona and sumatran and others... I just hope the decaf gene is a RECESSIVE. In fact I wouldn't mind if it was a DOUBLE RECESSIVE. That'd mean that you'd have to SPECIFICALLY BREED the plants to be decaf. That'd mean that all the new plants in the world would be fully caffienated. And caffiene is nice.
I would expect it to be recessive, but not double recessive. It's probably a defective gene for an enzyme involved in producing caffeine. If the plant has a non-defective gene for that enzyme, it will have the enzyme and be caffeinated, but if it doesn't have any non-defective copies of the gene, it won't have caffeine.