If memory serves, I've been hearing about "biotransformation" for a while now. The first time was in the context of Brett beers. I've heard several widely respected brewing folks talking about it in the context of ales, mostly New England IPA. I've even heard a Fullers brewer state that they dry hop London Pride during fermentation because of it. I figured someone must have finally done a scientific study and proved it's a thing.
But today I'm listening to Palmer on Basic Brewing Radio and he stated, with expert reference, that some wine strains and Brett strains have been proven to interact with hop glycocides and produce biotransformation, but to date there is no evidence that ale or lager yeast do this. In fact there are failed attempts to prove it. So at a minimum, biotransformation in S. Cerevisiae ales is unknown, and possibly its doubtful. If we are limited to the studies so far, we'd have to say it's not a thing.
Sad because I was buying what was being laid down, and started dry hopping my pales at day 3... although, unlike others I was not experiencing any new flavors from that. Until further data, I'm sticking with post fermentation dry hopping on the rare beers that I bother with it.
Awesome hobby, but you can't have too much CDO about facts remaining facts.
CDO is OCD with the letters in alphabetical order, the way they should be! (Just a little isolmerization humor)