no, gain of function means making a virus do something it couldn't otherwise, not just creating a more powerful strain through selective breeding. to do it they inject the virus into an animal with a characteristic they want, usually a bat or some exotic creature like a pangolin and then they allow the animal's dna to mix with it and affect it and then they kill the animal and extract the virus and repeat for hundreds of generations to force an evolutionary change where none could have occurred because the animal normally couldn't even contract the virus unless injected with it and the virus itself be modified with hiv which allows the virus to penetrate the cells in a way not possible in nature. the other method is through gmo radiation exposure which forces a genetic change to the virus when that level of radiation doesn't exist in nature. that's how gmo corn is made to create versions that sterilize the population and are resistant to roundup brand pesticides.
United States