How do these observations lead to a breeding technique where a plant ends up with fish DNA?
You'll notice the the events listed are either in related species, or from ecologically very tightly coupled species (eg, host and gut bacteria), and seem to imply time scales and population counts which are much higher than would be economically feasible for breeding.
Because there's no such thing as 'fish DNA'. There's just DNA. Its a code, and code doesn't 'belong' to any organism or know where its at. So transfer of DNA from one organism to another, like monkeys typing, increases the rate of change in species well above that of mutation alone.
