alt Hacker NewsI knew someone who started a farm of Spirulina (a microscopic, edible algae [cyanobacteria]) in a very different climate from where the seed culture originated. They did really poorly for the first few days, they were the wrong color and the culture wasn't growing. But eventually they adapted to the new climate and bounced back, and he was able to scale the culture up to multiple greenhouses and harvest it on an ongoing basis.
Before concluding a genetic change took place I would want to rule out alternative hypotheses. Maybe the cyanobacteria needed to do a mode switch which took time, maybe some parasite had to die, or some symbiote had to enter the culture. Yeah I'm just kinda throwing things out there, but still.