To the sound of loud yawns, in 1930 Dr Henry Dawson dared publicly suggest that a phenomenon he called 'bacterial transformation' (the name was general from the 1930s till the 1980s when it was replaced by today's horizontal gene transfer or HGT), could explain the mysterious and sudden rise of epidemics of new highly virulent diseases.
Sometimes, he thought, a previously mildly virulent pathogen suddenly acquires, from other species of organisms, a new gene or three that made this former 97 pound pathogenic weakling suddenly highly virulent against its traditional victims.
And we now also know that the human breeding of plants and animals for commercial exploitation can also instantly flood the world with an entire population of long domesticated beings with an 'improvement'---- that in fact suddenly makes them very vulnerable to a long existing, mild pathogen.
Dawson died in 1945, before he could point to a clear case of a new epidemic thrown up by HGT like behavior from the victim or the pathogen --- or both.
Victoria oats blight fell upon the world very suddenly in the late 1940s - the result of two genetic events colliding.
Man had introduced an new gene into commercial oat species that made them better resist the much feared crown rust fungus disease.
Great --- except that a mild pathogen of oats had also gained a new gene cluster from HGT.
One that normally would have been quickly lost by evolutionary pressure --- due to its added energy cost of making this new gene cluster versus null gain for the blight producer.
That now there were millions of acres of oats, all over the world, all bearing the a new gene that turned this pathogen's new virulency factor a decided advantage for it surviving and flourishing on oats.
Presto - all the world's oat crops, all with the same commercially-added gene, were suddenly under attack.
Science mucky--mucks investigated and reluctantly reversed one of their century old central dogmas --- that biodiversity was a bad bad bad thing (cue here, eugenics et al).
Amazing that anyone could make a million bucks (or get a PhD and do a post doctoral term of servitude) without ever hearing that old old folk saying about never putting all your eggs (or oat seed) in one basket, but there you are.
Commercial greed meet scientific hubris - you two suckers were born for each other ...